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914    Operative  and  dental 


RECAP 


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http://www.archive.org/details/operativedentalaOOmcge 


OPERATIVE 

AND 

DENTAL  ANATOMY  TECHNICS 


McG  E  H  E  E 


OPERATIVE 


AND 


DENTAL  ANATOMY  TECHNICS 

A  CLASS-ROOM  AND  LABORATORY  MANUAL 

FOR 

FRESHMEN  DENTAL  STUDENTS 


BY 

W.  H.  O.  McGEHEE,  D.  D.  S.,  M.  D. 

PROFESSOR  OF  OPERATIVE  AND  PROSTHETIC  DENTISTRY  AND  SUPERINTENDENT  OF  CLINICS  IN   THE 

OHIO  COLLEGE  OF  DENTAL  SURGERY;  FORMERLY  DEAN,  PROFESSOR  OF  DENTAL  PATHOLOGY, 

THERAPEUTICS   AND   MATERIA   MEDICA   AND   DEMONSTRATOR  OF  DENTAL  TECHNICS 

IN     THE     DEPARTMENT     OF    DENTISTRY     OF     THE    LINIVERSITY     COLLEGE    OF 

MEDICINE;     MEMBER    OF    THE     NATIONAL    DENTAL     ASSOCIATION, 

THE    VIRGINIA    STATE  DENTAL  SOCIETY,    THE   OHIO   STATE 

DENTAL    SOCIETY    AND    THE     CINCINNATI     DENTAL 

SOCIETY;     MEMBER     OF     THE      COMMISSION 

ON    OPERATIVE    TECHNICS    OF    THE 

INSTITUTE   OF  DENTAL 

PEDAGOGICS 


ILLUSTRATED  WITH  235  ENGRAVINGS 


PHILADELPHIA 

P.   BLAKISTON'S   SON   &   CO. 

1012  WALNUT   STREET 
1914 


Copyright,  1914,  by  P.  Blakiston's  Son  &  Co. 


THE . MAPLE. PRESS- TOKK. PA 


DEDICATION. 

TO 

HELEN  NYE, 

FAITHFUL  AND  LOVING  WIFE,  WHO,  BY  HER   INFINITE 

PATIENCE,    INTELLIGENT   COUNSEL.   UNSELFISH 

SACRIFICES  AND  UNFAILING  INTEREST  AND 

DEVOTION,  INSPIRES  ALL  HIS  EFFORTS, 

THIS  BOOK  IS  DEDICATED  BY  HER 

HUSBAND,     THE  AUTHOR. 


PREFACE 


"  The  permanence  of  all  hooks  is  fixed  by  no  effort  friendly 
or  hostile,  hut  by  their  own  specific  gravity,  or  the  intrinsic 
importance  of  their  contents  to  the  constant  mind  of  man.'' — 
Emerson. 

■  While  this  book  is  written  primarily  to  hll  a  long-felt  need 
in  presenting  the  subjects  of  Dental  Anatomy  and  Operative 
Technics  before  his  own  classes,  the  author  believes  it  will  also 
meet  the  needs  of  teachers  of  the  subject  in  other  schools,  and 
relieve  them  of  the  tedium  of  culling  from  larger  texts  material 
for  the  preparation  of  lectures  and  the  mapping  out  of  an 
adequate  technic  course. 

The  existence  of  two  such  excellent  works  on  Dental 
Anatomy  as  those  of  Broomell-Fischelis  and  Black  precludes 
the  necessity  of  another.  The  chapter  on  Dental  Anatomy, 
then,  is  intended  only  as  an  aid  to  the  teaching  and  study 
of  one  or  the  other  of  these  books,  outlining  a  technic  course  on 
the  subject,  modeled  to  suit  the  needs  of  the  average  student 
after  consultation  with  some  of  the  most  prominent  teachers 
of  the  subject  in  this  country.  The  book  is  not  intended  to 
supplant  the  text-books  on  Operative  Dentistry  at  present  in 
use;  but  it  is  a  recognized  fact  that  these  are  all  too  voluminous 
for  use  as  a  text  by  freshmen  students,  in  acquiring  the  limited 
knowledge  of  the  subject  necessary  for  the  performance  of  the 
various  exercises  in  the  operative  technic  laboratory.  No 
especial  effort,  therefore,  has  been  made  to  enter  into  a  dis- 
cussion of  the  causes  of  things,  leaving  a  consideration  of  the 
why  and  wherefore  for  investigation  on  the  part  of  the  student 


Vlll  PREFACE 


in  his  junior  and  senior  years.  The  effort  has  been  made  to  so 
condense,  simpHfy  and  systematize  the  presentation  of  the 
subject  matter  that  it  will  at  once  attract  the  eye  and  hold  the 
attention  of  the  as  yet  untrained  mind. 

Very  little  of  originality,  except  in  the  presentation  of  the 
subject,  is  claimed  for  the  work,  the  author  having  in  the  main 
followed  the  accepted  teachings  of  such  writers  as  G.  V.  Black, 
A.  E.  Webster,  Thomas  E.  Weeks,  D.  M.  Cattell,  Fred  W. 
Gethro,  C.  N.  Johnson,  D.  M.  GalHe,  Marcus  L.  Ward,  John 
Sayre  Marshall,  I.  N.  Broomell,  Philipp  Fischelis,  Otto  E. 
Inglis,  J.  P.  Buckley,  L.  M.  Waugh,  Chas.  J.  Essig,  Augustus 
Koenig,  J.  D.  Hodgen,  W.  Clyde  Davis  and  others. 

The  writer  has  endeavored  to  follow  out  in  the  presentation 
of  the  subject  the  ideas  accepted  and  recommended  by  the 
Institute  of  Dental  Pedagogics  as  incorporated  in  the 
published  transactions  of  that  body,  and  the  work  has  been 
examined  by  the  Commission  on  Text-books  of  that  or- 
ganization. 

The  technic  exercises  have  been  outlined  after  a  study  of 
the  courses  as  taught  in  many  of  the  prominent  schools,  and 
after  an  experience  of  fifteen  years  as  a  teacher  of  the  subject. 
They  may  be  modified  according  to  the  judgment  of  the  teacher 
to  suit  the  needs  of  any  classes. 

If  the  work  proves  to  be  of  assistance  to  teachers  in  out- 
lining their  courses  and  to  the^great  body^of  young"men  yearly 
entering  upon  the  study  of  a  noble  profession,  in  acquiring  a 
knowledge  of  the  subjects  of  Dental  Anatomy  and  elementary 
Operative  Dentistry,  the  author  will  feel  well  repaid  for  the 
labor  expended  in  its  preparation. 

Cincinnati,  Ohio,  1913. 


CONTENTS 


Page 

Preface v 

A  Talk  with  the  Student 

CHAPTER  I 

Dental  Anatomy i 

How  to  Study  it — How  to  Perform  the  Technic  Operations — How  to 
Review  for  Examination. 

CHAPTER  II 

iNSTRtJMENTS    AND    APPLIANCES 41 

CHAPTER  III 

Preparation   of    Cavities 9° 

CHAPTER  IV 

Filling  Materials 120 

CHAPTER  V 

The  Treatment  of  Pulps  and  the  Opening  and  Filling  of  Pulp-cham- 
bers AND  Canals 164 

CHAPTER  VI 

Suggestions  to  the  Teacher 1S2 

Technic  Course  Suggested  by  the  Author iQS 

Index 201 


LIST  OF  ILLUSTRATIONS 

Pig.  Pace 

1.  Occlusion  of  the  teeth,  anterior  view 2 

2.  Occlusion  of  the  teeth,  lateral  view 3 

3.  The  upper  aich 4 

4.  The  lower  arch 5 

5.  The  facial  angle  and  line  of  occlusion 6 

6.  The  compensating  cur\'e 7 

7.  Right  upper  central  incisor,  labial  surface 13 

.8.  Upper  central  incisor,  mesial  surface 13 

0.  Right  upper  central  incisor 14 

10.  Right  uppei  cuspid 14 

11.  Right  upper  cuspid 15 

12.  Right  upper  first  bicuspid.     Buccal  surface i^ 

13.  Uppei  fiist  bicuspid.     Mesial  surface 16 

14.  Right  upper  second  bicuspid 16 

15.  Lower  first  bicuspid 16 

16.  Left  upper  first  bicuspid.     Occlusal  surface       ly 

17.  Right  lower  second  bicuspid.     Occlusal  surface 17 

18.  Upper  and  lower  bicuspids 17 

19.  Right  upper  first  molar.     Buccal  surface 18 

20.  Right  upper  first  molar.     Occlusal  surface 18 

21.  Right  upper  second  molar.     Occlusal  surface iq 

22.  Right  upper  third  molar.     Occlusal  surface ig 

23.  The  molar  triangle 20 

24.  Surfaces,  line  and  point  angles,  lower  molars 21 

25.  Left  lower  first  molar.     Buccal  surface 22 

26.  Left  lower  second  molar.     Buccal  surface 22 

27.  Left  lower  first  molar.     ^Mesial  surface 22 

28.  Left  lower  first  molar.     Occlusal  surface 23 

29.  Right  lower  second  molar.     Occlusal  surface 23 

30.  Occlusion  of  the  teeth 23 

31.  Inclination  of  the  anterior  teeth 24 

32.  Mesial  inclination  of  the  upper  centrals 24 

33.  Inclination  of  the  molars 24 

34.  Upper  central  incisor;  enamel,  dentin,  cementum  and  pulp 25 

35.  Technic  of  carving  in  ivory 28 

36.  Technic  of  carving  in  ivory 28 

37.  Technic  of  carving  in  ivory 28 

38.  Technic  of  carving  in  ivory 28 

39.  Technic  of  carving  in  ivory 29 

xi 


Xll  LIST    OF    ILLUSTRATIONS 

Fig.  Page 

40.  Technic  of  carving  in  ivory 29 

41.  Technic  of  carving  in  ivory 29 

42.  Carvings  in  ivory 30 

43.  Longitudinal  section,  upper  central  incisor 32 

44.  Longitudinal  section,  lower  central  incisor 32 

45.  Tooth  mounted  on  a  wood  block 33 

46.  Gingival  section  of  an  upper  central  incisor .  33 

47.  Mid-root  section  of  an  upper  central  incisor 34 

48.  Apical  third  section  of  an  upper  central  incisor 34 

49.  Method  of  mounting  a  box  of  sections 35 

50.  Page  from  a  book  of  prints 37 

51.  Vulcanite  instrument  handles 45 

52.  Steel  instrument  handles 45 

53.  Pen  grasp,  rest  and  guard 47 

54.  Palm  and  thumb  grasp 48 

55.  The  guard 49 

56.  The  centigrade  circle 50 

57.  The  dental  instrument  gauge 51 

58.  Measuring  the  angle  of  the  blade  with  its  shank 52 

59.  Hatchet  excavator 53 

60.  The  Boley  millimeter  gauge 54 

61.  Black  cutting  instruments 57 

62.  Chisels 58 

63.  Engine  burs,  enlarged 58 

64.  The  round  bur,  enlarged 59 

65.  Enlarged  dentate  burs 59 

66.  Spear-point  drills 59 

67.  Square  drills 59 

68.  Twist  driUs 60 

69.  Gates-Glidden  reamers ' 60 

70.  Kerr  tapered  canal  reamers 61 

71.  Bistouries 61 

72.  S.  S.  W.  scalers 62 

73.  Tompkin's  scalers 62 

74.  Black  files     63 

75.  Flexo  file 64 

76.  Kaeber  saw-frame  and  saw 64 

77.  Black  knives 65 

78.  Pichler  knives 65 

79.  Carborundum  wheels 65 

80.  Carborundum  points 65 

81.  Soft  rubber  poUshing  points 66 

82.  Emery  cloth  disks 66 

83.  Carborundum  disks 66 

84.  Disk  mandrel 66 

85.  Arkansas  stone 67 


LIST    OF    ILLUSTRATIONS  XIU 

Flo.  Pack 

86.  Black  gold  pluggcrs 68 

87.  Varncy  gold  pluggcrs 68 

88.  Enlarged  nibs  of  the  Black  gold  pluggcrs 69 

89.  Enlarged  nibs  of  the  Black  gold  pluggcrs 69 

90.  Enlarged  nibs  of  the  Black  gold  pluggcrs 70 

91.  Black  amalgam  pluggers 71 

92.  Loaded  amalgam  carrier  and  plugger 72 

93.  Burnisher 72 

94.  Burnisher 73 

95.  Thin  burnishers 73 

96.  German  silver  cement  spatulas 74 

97.  Automatic  plugger 74 

98.  Double  end  cavity  explorers 74 

99.  Enlarged  barbed  broach 75 

100.  S.  S.  W.  canal  cleaners 75 

loi.  Kerr  spiral  broaches 75 

102.  Metal  broach  handle 75 

103.  Ivory  universal  double-bow  separator 76 

104.  Ivory  separator 76 

105.  Perr}'  separators 77 

106.  Elliot  separator 77 

107.  Ivory  matrix  retainer  No.  i  and  bands 78 

108.  Ivory  matrix  retainer  No.  8  and  bands 78 

109.  S.  S.  W.  rubber  dam  clamps  for  molars 79 

no.  S.  S.  W.  rubber  dam  clamps  for  anterior  teeth 80 

111.  Rubber  dam  clamp  forceps 81 

112.  Ivory  cervical  clamp 82 

113.  Johnson  cervical  clamp 82 

114.  How  cervical  clamp 82 

115.  Adjusting  the  dam 82 

116.  The  rubber  dam  adjusted 82 

117.  Mouth  mirror gi 

118.  Water  syringe,  rubber  bulb 83 

119.  Chip  blower 3^ 

1 20.  Ainsworth  rubber  dam  punch 84 

121.  Alcohol  lamp,  flame  shield  and  annealer 84 

122.  Revolving  head  bur-holder 85 

123.  Dental  engine gr 

124.  Insrutment  technic  in  brass gg 

125.  Outline  form,  occlusal  cavities gg 

126.  Outline  form,  occlusal  ca\aties pg 

127.  Outline  form,  occlusal  cavities gg 

128.  Outline  form,  occlusal  cavities gg 

129.  Outline  form,  occlusal  cavities 100 

130.  Outline  form,  occlusal  cavities 100 

131.  Outline  form,  proximal  cavitv loi 


xiv  LIST    OF    ILLUSTRATIONS 

Fig.  Page 

132.  Mortise  form,  simple  on  one  surface 10: 

133.  Mortise  form,  simple  dov^etail,  one  surface 10: 

134.  Mortise  form,  simple,  invohdng  two  surfaces 10: 

135.  Mortise  form,  simple  dovetail,  two  surfaces 102 

136.  Mortise  form,  compound lo' 

137.  Mortise  form,  compound  dovetail 10-" 

138.  Cavity  in  central  fossa,  upper  molar 103 

139.  Cavity  in  occlusal  groove,  upper  bicus{)id 103 

140.  Labial  cavity,  upper  central  incisor 103 

141.  Labial  ca\dty,  upper  cuspid 103 

142.  Lingual  ca\ity,  upper  lateral 103 

143.  Buccal  cavity,  bicuspid 104 

144.  Disto-occlusal  cavity,  upper  molar 104 

145.  Mesio-occlusal  cavity,  upper  bicuspid 104 

146.  Mesio-occlusal  cavity,  upper  molar 104 

147.  Occlusal  cavity,  upper  molar 10s 

148.  Occlusal  cavity,  upper  molar 105 

149.  Mesial  cavity,  upper  central  incisor lod 

150.  Lingual  view  of  same  cavity  shown  in  Fig.  149 io() 

151.  Another  aspect  of  cavity  shown  in  Figs.  149  and  150 106 

152.  Mesio-incisal  cavit)^,  upper  central  incisor 107 

153.  Mesio-incisal  cavity,  upper  central  incisor 107 

154.  Lingual  step  form,  upper  lateral  incisor 107 

155.  Lingual  step  form,  upper  lateral  incisor 107 

156.  Proximal  cavity,  bicuspid loS 

157.  Proximo-occlusal  cavity,  bicuspid loS 

158.  Proximo-occlusal  cavity,  bicuspid log 

159.  Incisal  step  form,  upper  incisor I0() 

160.  Step  form,  upper  cuspid no 

161.  Mesio-incisal  cavity,  upper  cuspid no 

162.  Convenience  and  retention  form ii^' 

163.  Diagram  of  enamel  rods,  bicuspid 113 

164.  Diagram  of  enamel  rods,  molar 113 

165.  Diagram  of  enamel  rods,  incisor 114 

166.  Diagram  of  enamel  rods,  incisor 114 

167.  Cavity  preparation  in  bone  handle ii'i 

168.  Cavity  preparation  in  bone  handle iid 

169.  Celluloid  block  for  cavity  preparation ii'i 

170.  Plaster  technic  model 117 

171.  Plaster  technic  model 117 

172.  Flagg's  gutta-percha  and  tool  heater i2'i 

173.  Thermoscopic  gutta-percha  heater i2'» 

174.  Glass  cement  slab 121) 

175.  Glass  mortar  and  pestle i3'i 

176.  Making  the  roll 140 

177.  The  roll  complete 140 


LIST    or    ILLUSTRATIONS  XV 

Fig.  Page 

178.  Folding  the  ribbon 141 

179.  Making  the  cyhnder 142 

180.  Plugger  handles i44 

181.  Working  gold  or  tin  cylinders 14S 

182.  The  ribbon  method 146 

183.  Filling  step  cavity  with  cylinders,  first  stage i47 

184.  Filling  step  cavity  with  cylinders,  second  stage 147 

185.  Filling  step  cavity  wth  cylinders,  third  stage i47 

186.  Flame  shield  and  gold  annealer 151 

187.  Filling  "gingival  third"  cavity,  first  stage IS3 

188.  Filling  " gingival  third "  cavity,  second  stage iS3 

189.  Filling  "gingival  third"  cavity,  third  stage iS3 

Filling  "gingival  third"  cavity,  fourth  stage iS3 

Filling  "gingival  third"  cavity,  fifth  stage iS3 

Filling  proximal  cavity,  first  stage i54 

Filling  proximal  cavity,  second  stage iS4 

Filling  proximal  cavity,  third  stage iSS 

Filling  proximal  cavity,  fourth  stage i55 

Filling  proximo-occlusal  cavity,  first  stage iSS 

Filling  proximo-occlusal  cavity,  second  stage i5S 

198.  Filling  proximo-occlusal  cavity,  third  stage 156 

199.  Filling  proximo-occlusal  cavity,  fourth  stage 156 

200.  Filling  proximo-occlusal  cavity,  fifth  stage 156 

201.  Filling  proximo-occlusal  cavity,  sixth  stage iS^ 

202.  Filhng  proximo-occlusal  cavity,  seventh  stage iS7 

203.  Laminating  the  gold 158 

204.  Gold  burnishers 160 

205.  Removing  excess  at  the  gingival 160 

206.  Application  of  the  file  in  polishing 161 

207.  Filing  buccal  and  lingual  margins 162 

208.  Use  of  the  stone  in  polishing 162 

209.  Polishing  with  the  disk 162 

210.  Application  of  the  polishing  strip ,  162 

211.  Polishing  the  contact  point 163 

212.  Bicuspid  rubber  dam  clamps 167 

213.  Opening  into  the  chamber  and  canal I73 

214.  Opening  into  the  chamber  and  canal i73 

215.  Opening  into  the  chamber  and  canal 1 74 

216.  Opening  into  the  chamber  and  canal i74 

217.  Opening  into  th^chamber  and  canal 176 

218.  Opening  into  the  chamber  and  canal 176 

219.  Reaming  the  canal i77 

220.  Enlarging  canals  with  a  nub  broach i77 

221.  Measuring  the  length  of  the  canal 180 

222.  Gutta-percha  canal  points 181 

223.  Enlarged  aluminum  model , 186 


XVI  LIST    OF    ILLUSTRATIONS 

Fig.  Page 

224.  Enlarged  aluminum  model 187 

225.  Enlarged  technic  model  and  instruments 188 

226.  Enlarged  technic  model  and  instruments 189 

227.  Enlarged  technic  model  and  instruments 189 

228.  Excavator  blanks 190 

229.  The  typodont,  No.  i 192 

230.  The  typodont,  No.  2 192 

231.  The  odontotype,  Nos.  i  and  2 193 

232.  The  odontotype,  Nos.  6  and  7 194 

233.  Wright  dental  manikin 194 

234.  Wright  dental  manikin 195 

235.  Wright  dental  manikin 195 


A  TALK  WITH  THE  STUDENT 

"  Tlie  greatest  trust  between  man  and  man  is  the  trust  of 
giving  counsel.^' — Francis  Bacon. 

"How  to  live,  that  is  the  essential  question  for  us.'' — Herbert 
Spencer. 

Dear  Student: 

You  are  now  entering  upon  the  serious  study  of 
an  elevated  and  noble  profession,  with  your  banner  unfurled 
to  the  breeze  and  hope  beating  high  in  your  breast.  Advice 
from  one  who  has  passed  through  the  same  experiences  which 
are  soon  to  be  yours  should  not  be  amiss. 

You  are  now  laying  the  foundations  for  your  professional 
career.  Let  me  urge  you  to  place  them  deeply  and  broadly,  in 
order  that  they  may  not  totter  and  succumb  under  the  weight 
of  the  superstructure  which  is  to  be  raised  upon  them  during 
the  years  to  come.  Your  college  life  is  the  most  important 
part  of  this  architectural  design.  Your  character  is  now  in 
the  process  of  formation,  whether  you  will  or  no;  habits  are 
being  formed,  friendships  are  being  made,  which  will  influ- 
ence your  entire  hfe.  This  being  the  case,  it  behooves  you 
to  pause  with  me  for  a  few  moments  and  consider  the  situa- 
tion— to  take  a  mental  view  of  the  landscape,  which  appears 
so  bright  and  rosy  and  full  of  promise. 

Let  me  urge  you  to  be  careful  in  selecting  your  social  com- 
panions. You  are  probably  now  in  a  strange  city,  surrounded 
by  many  temptations,  away  from  home  restraints  and  the 
loving  counsels  of  your  parents,  who,  expecting  much  of  you, 
have  sent  you  forth  into  the  world  to  fulfill  your  mission  in 

xvii 


XVni  A   TALK   WITH   THE    STUDENT 

life.  Do  not  allow  them  to  be  disappointed.  The  care  with 
which  you  choose  your  friends,  the  selection  of  the  social 
circle  in  which  you  are  to  move,  will  greatly  influence  the 
development  of  your  character  and  that  personality  which  is 
to  make  or  mar  your  future. 

You  should  respect  and  endeavor  to  follow  to  the  utmost 
the  advice  and  teachings  of  your  instructors.  Make  diligent 
effort  to  master  the  theoretical  and  technical  studies  with 
which  you  will  be  surrounded  throughout  your  college  course. 
Many  students  make  the  error  of  feeling  satisfied  if  they  have 
made  a  passing  grade  on  theory  and  have  more  or  less  satis- 
factorily completed  the  requirements  designated  by  the  fac- 
ulty of  the  school.  You  will  make  a  serious  mistake  if  you 
allow  only  this  to  be  your  aim,  as  you  will  fall  far  short  of 
bringing  out  the  best  of  your  capabilities.  Let  me  advise 
you  to  look  at  the  matter  from  a  much  broader  standpoint. 
Your  chief  aim  should  be  to  endeavor  so  to  equip  your- 
self for  your  life's  work,  and  so  to  perfect  yourself  in 
your  chosen  profession,  that  you  may  be  enabled  to  stand 
shoulder  to  shoulder  with  your  future  co-laborers,  and  intelli- 
gently serve  those  to  whom  you  expect  to  minister. 

Some  are  endowed  with  ambition  to  excel  and  stand  above 
their  fellows.  Perhaps  you,  yourself,  already  have  this  idea, 
or  have  your  thoughts  fixed  toward  some  prize  which  is 
offered  by  your  teacher.  This  is  all  very  well,  but  the  idea 
of  primarily  working  for  a  prize  or  reward  does  not  always 
stimulate  to  the  best  efforts.  John  Ruskin  says:  "A man  or 
woman  in  private  or  public  life,  whoever  works  only  for  the 
sake  of  the  reward  which  comes  for  the  work  will  in  the  long 
run  do  poor  work  always.  I  do  not  care  where  the  work  is, 
the  man  or  woman  who  does  work  worth  doing  is  the  man  or 
woman  who  lives,  breathes,  and  sleeps  that  work,  with  whom 
it  is  ever  present  in  his  or  her  soul;  whose  ambition  it  is  to  do 


A    TALK    WITH    THE    STUDENT  XIX 

//  well  and  feel  rewarded  by  (he  thought  of  having  done  it  well. 
That  man  or  woman  puts  the  whole  country  under  an  obli- 
gation." Read  the  quotation  again!  The  italics  have  been 
placed  there  by  myself,  because  that  is  the  important  clause. 
Do  your  work  well,  not  primarily  for  the  sake  of  any  pecuniary 
reward  or  attractive  prominence  which  it  may  give  you,  but 
to  satisfy  your  own  conscience.  Ralph  Waldo  Emerson  means 
practically  the  same  thing  when  he  says:  "Work  in  every 
hour,  paid  or  unpaid,  see  that  thou  work  and  thou  canst  not 
escape  the  reward;  whether  thy  work  be  fine  or  coarse,  plant- 
ing corn  or  writing  epics,  so  only  it  be  honest  work,  done  to 
thine  own  approbation,  it  shall  earn  a  reward  to  the  senses  as 
well  as  to  the  thought;  no  matter  how  often  defeated,  you  are 
born  to  victory.  The  reward  of  a  thing  well  done  is  to  have 
done  it." 

I  would  impress  upon  you  the  broad  scope  and  scientific 
nature  of  the  profession  which  you  are  entering.  The  dentist 
is  constantly  working  on  living  tissues  which  have  an  inti- 
mate relationship  with  all  parts  of  the  body.  His  work  is 
founded  on  a  thorough  knowledge  of  Anatomy,  Physiolog}-, 
Chemistry,  Materia  Medica  and  Pathology,  as  well  as  an 
understanding  of  physical  and  mechanical  laws.  He  should 
at  all  times  be  prepared  to  write  prescriptions  for  the  treatment 
of  oral  diseases;  he  should  be  fully  competent  to  make  a  phys- 
ical inspection  of  the  heart  and  lungs,  as  well  as  an  examina- 
tion of  the  saUvary  and  other  secretions  of  the  body;  he  should 
understand  the  ad  ministration  of  general  and  local  anesthetics, 
his  sense  of  the  esthetic  and  artistic  must  be  highly  developed; 
and  he  must  be  prepared  to  do  many  other  things  of  which 
you  will  learn  later  in  your  course.  Do  not  imagine,  then, 
that  your  chief  functions  are  to  be  those  of  the  artisan  or 
mechanic.  He  who  holds  this  narrow  \iew  of  the  profession 
and  imagines  that  dentistry  consists  largely  in  the  packing 


XX  A   TALK   "WITH   THE    STUDENT 

of  a  little  gold  or  amalgam  into  a  cavity  in  a  tooth  is 
wanting  in  knowledge. 

In  addition  to  perfecting  yourself  in  a  knowledge  of 
dentistry  I  would  advise  that  you  devote  a  portion  of  your 
time  to  the  acquirement  of  general  information.  There  is 
nothing  which  has  a  more  broadening  influence  than  the  read- 
ing of  good  literature.  The  man  who  knows  nothing  outside 
of  his  own  calling  soon  degenerates  and  becomes  small  and 
narrow.  The  public  expects  the  professional  man  to  know 
something  about  everything,  and  will  frequently  place  a  low 
estimate  on  your  ability,  if  you  do  not  measure  up  to  its 
expectations  in  this  direction. 

You  should  not  only  continue  the  pursuit  of  general  and 
professional  knowledge,  but  should  also  sedulously  cultivate 
the  habit  of  close  observation  and  investigation.  Learn  how 
to  exercise  the  faculty  of  thought  and  thus  develop  ideas  of 
your  own.  "Read  not  to  contradict  and  confute,  nor  to  be- 
lieve and  take  for  granted,  nor  to  find  talk  and  discourse,  but 
to  weigh  and  consider.  Some  books  are  to  be  tasted,  others 
to  be  swallowed  and  some  few  to  be  chewed  and  digested." — 
Lord  Bacon. 

Close  attention  to  minutiae  and  detai]  are  possibly  of  more 
importance  in  dentistry  than  in  any  other  vocation.  When 
one  remembers  the  small  size  of  the  oral  cavity  and  the  many 
minute  and  delicate  operations  which  the  dentist  is  constantly 
called  upon  to  perform  within  this  limited  field,  then  only  can 
one  appreciate  the  importance  of  absolute  exactness  and  at- 
tention to  detail  in  the  work.  Each  step  of  every  operation 
should  be  made  perfect  before  another  is  undertaken,  if  a 
perfect  result  is  to  be  obtained.  No  part  can  be  slighted  or 
hurried.  Make  up  your  mind  now  never  to  let  a  piece  of  de- 
fective work  go  from  your  hands.     Do  it  over  and  over  again 


A    TALK    WITH    THE    STUDENT  XXI 

until  you  have  done  your  very  best.     Your  conscience  is  your 
best  mentor  in  this,  as  in  everything  else. 

Your  constant  aim  should  be  perfection.  Set  the  word 
Perfection  up  as  your  ideal  and  make  it  your  daily  endeavor 
to  reach  that  ideal.  He  who  constantly  works  with  that  end 
in  \icw  will  make  a  success  in  his  calling. 

*  "  If  a  man  can  write  a  better  Book — 
Or  preach  a  better  Sermon — 
Or  make  a  better  Mousetrap  than  his  neighbor — 
Though  he  build  his  house  in  the  w^oods, 
The  world  would  make  a  beaten 
Track  to  his  door." 

And  now,  dear  student,  I  could  go  on  and  on,  but  it  is  not 
necessary.  If  you  will  follow  the  precepts  here  laid  down  for 
your  guidance  you  will  never  have  cause  for  regret.  With 
the  hope  that  the  following  pages  may  be  of  interest  and 
benefit,  I  will  repeat  to  you  the  advice  of  Polonius  to  his  son, 
who  was  leaving  home  for  a  journey  into  France: 

Polonius:  Yet  here,  Laertes!  aboard,  aboard,  for  shame! 
The  wind  sits  in  the  shoulder  of  your  sail, 
And  you  are  stay'd  for.     There;  my  blessing  with 

thee! 
And  these  few  precepts  in  thy  memory 
See  thou  character.     Give  thy  thoughts  no  tongue, 
Nor  any  unproportion'd  thought  his  act. 
Be  thou  familiar,  but  by  no  means  vulgar. 
Those  friends  thou  hast,  and  their  adoption  tried, 
Grapple  them  to  thy  soul  with  hoops  of  steel; 
But  do  not  dull  thy  palm  wdth  entertainment 
Of  each  new-hatch'd,  unfledged  comrade.     Beware 
Of  entrance  to  a  quarrel,  but  being  in, 

*Atlributed  to  Emerson,  though  not  proven. 


XXll  A    TALK   WITH   THE    STUDENT 

Bear't  that  the  opposed  may  beware  of  thee. 

Give  every  man  thy  ear,  but  few  thy  voice; 

Take  each  man's  censure,  but  reserve  thy  judgment. 

Costly  thy  habit  as  thy  purse  can  buy, 

But  not  express'd  in  fancy;  rich,  not  gaudy; 

For  the  apparel  oft  proclaims  the  man. 

And  they  in  France  of  the  best  rank  and  station 

Are  of  a  most  select  and  generous  chief  in  that. 

Neither  a  borrower  nor  a  lender  be; 

For  loan  oft  loses  both  itself  and  friend, 

And  borrowing  dulls  the  edge  of  husbandry. 

This  above  all;  to  thine  own  self  be  true. 

And  it  must  follow,  as  the  night  the  day. 

Thou  cans't  not  then  be  false  to  any  man. 

Farewell;  my  blessing  season  this  in  thee! 

(Hamlet,  Act  I.,  Scene  III.) 


OPERATIVE  AND  DENTAL  ANATOMY 
TECHNICS 


CHAPTER  I 

DENTAL  ANATOMY 

HOW  TO  STUDY  IT— HOW  TO  PERFORM  THE  TECH- 
NIC  OPERATIONS— HOW  TO  REVIEW  FOR  EX- 
AMINATION 

Text-hooks. — Dental  Anatomy,  Black;  or  Anatomy  and  Histology  of  the 
Mouth  and  Teeth,  Broomell  and  Fischelis. 

HOW  TO  STUDY  THE  SUBJECT 

The  study  of  Dental  Anatomy  will  develop  into  an  inter- 
esting and  profitable  pastime  or  a  dull  and  lifeless  labor,  de- 
pending upon  the  standpoint  from  which  its  intricacies  are 
approached.  In  a  sense,  it  is  really  the  foundation  on  which 
is  to  be  built  all  dental  knowledge,  a  thorough  familiarity  with 
the  externa]  and  internal  forms  of  the  teeth,  their  points  of 
interest  and  their  intimate  relationships  with  each  other  being 
absolutely  essential  to  a  complete  understanding  of  the  other 
branches  of  the  curriculum.  It  has  a  direct  bearing  on  all  of 
these  subjects,  and  the  student  should  realize  now  that  if  he 
wishes  to  become  proficient  in  the  science  and  art  of  filling 
teeth,  of  making  crowns,  bridges  and  plates,  and  all  of  the 
procedures  incident  to  the  practice  of  dentistry,  he  should  first 
learn  this  subject.     In  making  the  drawings,  carving  the  blocks 


2  DENTAL   ANATOMY 

and  filing  the  sections — in  performing  all  the  technic  opera- 
tions— he  should  do  so  intelligently  and  thoroughly,  and  with 
the  view  to  deriving  as  much  practical  benefit  as  possible  from 
the  procedures;  else  much  of  his  time  is  being  wasted  and  the 
work  rapidly  degenerates  into  uninteresting  drudgery. 

(The  appended  references  refer  to  paragraph  numbers  in^ 


Fig.  I. — Occlusion  of  the  teeth.    Anterior  view. 

Black's  Dental  Anatomy,  or  to  page  numbers  in  the  text  or  in 
Broomell  and  Fischelis'  Anatomy  and  Histology  of  the  Mouth 
and  Teeth.  B.  =  Black;  B.F.  =  Broomell  a,nd  Fischelis; 
Par.  =   paragraph;  pp.  =  page;  fig.  =  figure.) 

I.  Study  the  Glossary  of  Black's  Dental  Anatomy.     B.  pp. 
IX-XVII. 


HOW   TO   STUDY   THE   SUBJECT  3 

2.  Study  the  names,  number  and  arrangement  of  the  teeth, 
in  the  upper  and  lower  jaw.     B.  par.  i,  2,187/0192.     B.F. 

PP-  n,  74- 

3.  Study  the  general  characteristics  of  the  teeth  and  the  form 


Fig.  2. — Occlusion  of  the  teeth.    Lateral  view. 

of  the  arch  in  the  sanguine,  bilious,  nervous  and  lymphatic 

temperaments.     B.  fig.   126,  par.   187  to  188.     B.F.  pp. 
11,  78,  ^Z- 
4.  Study  the  occlusion  of  the  teeth  (Figs,  i  and  2).     B.  par. 
190.     B.F.  pp.  85  to  90.       ^ 


DENXAjL   ANATOMY 

Distinguish  the  difference  between  occlusion  and  articula- 
tion.    B.F.  pp.  85  and  86. 

Distinguish  between  the  interproximal  space  and  the  inter- 
proximal embrasure.     B.  par.  13,  193  and  194. 
Study  the  formula  for  the  permanent  and  deciduous  teeth. 
B.  par.  2  and  128.     B.F.  pp.  75.   . 


*"  Fig.  3. — The  upper  arch. 


8.  Learn  Palmer's  notation.     Text  pp.  g. 

9.  Remember  that  the  gingival  line  of  Black  and  the  cer- 
vical line  of  Broomell  are  the  same.  B.  par.  3.  B.F. 
\pp.  lOI. 

10.  Remember  that  Broomell  calls  the  free  margin  of  the  gum 


now    TO    STUDY   THE    SUBJECT  5 

the  gingival  line,  wliile  Black  speaks  of  it  as  the  gingiva 
or  gingival  margin.     B.  par.  211,  B.F.  pp.  loi. 

11.  Study  the  characteristics  of  the  tissues  of  which  a  tooth 
is  composed.     B.F.  pp.  72. 

12.  Study  and  learn  the  definition  of  the  parts  of  a  tooth,  such 


F;G.  4. — The  lower  arch. 

as  crown,  root,  neck,  apex,  pulp  chamber,  canals,  apical 
foramen;  also  the  names  of  the  surfaces  and  angles. 
B.  par.  3,  4,  5,  6,  7,  8.     B.F.  pp.  72  and  75. 

13.  Study  the  difference  between  a  cusp  and  a  tubercle;  a 
fossa,  sulcus,  groove,  and  fissure.  B.  Glossary.  Also 
par.  8,  10,  II. 

14.  Distinguish'between  the  three  varieties  of  ridge.    B.  par.  9. 


6  DENTAL  ANATOMY 

15.  Distinguish  between  the  three  varieties  of  groove.  B. 
par.  II  and  12. 

16.  Study  the  relation  of  the  line  of  occlusion  to  the  facial 
angle  (Figs.  5  and  6).     B.F.  pp.  87  and  88. 

17.  Study  the  difference  between  the  thick  neck  and  bell- 
crown  teeth  and  the  bearing  of  these  on  the  shape  of  the 


Fig.  5. — The  facia]  angle  and  line  of  occlusion.  ' 

interproximal  space  and  the  shape  and  size  of  the  contact 
point.     B.  par.  14,  18,  194,  195.    B.F.  pp.  83. 

18.  Study  the  method  of  attachment  of  the  teeth  in  the  sockets. 
B.  par.  196,  197,  206.     B.F.  pp.  73. 

19.  Study  the  upper  and  lower  incisors  as  a  group,  noting 
differences  in  shape,  size,  location  and  inclination.     B. 


HOW   TO    STUDY    THE    SUBJECT  7 

par.  i6  /(>3i,  191  to  192.     B.F.  pp.  nolo  124,  172  to  177 — 
also  78,  79,  80,  81  and  82. 
20.  Study  the  surfaces,  margins,  angles,  ridges,  grooves  and 
lobes  of  these. 


Fig.  6. — The  compensating  curve  or  the  curve  of  Spec. 

21.  Study  the  upper  and  lower  cuspids  in  the  same  manner. 

22.  Study  the  upper  and  lower  bicuspids  together  in  the  same 
way. 

23.  Study  the  molars. 

24.  Study  the  dijfferences  between  the  permanent  and  de- 


5  DENTAL   ANATOMY 

ciduous  teeth  as  to  number,  size,  shape,  color,  length  of 
roots,  constriction  of  neck  and  inclination  of  buccal  and 
lingual  surfaces.     B.  par.  128  to  133.     B.F.  pp.  224,  225. 

25.  Study  the  anatomy  of  the  temporary  first  and  second 
molars,  upper  and  lower.  B.  par.  129,  134  to  151.  B.F. 
pp.  2^1  to  22,3,  2s6  to  2sS. 

26.  Study  the  form  and  size  of  the  pulp  chamber  and  canals 
in  the  permanent  teeth  while  making  the  sections  and 
prints  in  the  technic  course. 

27.  Select  from  a  miscellaneous  lot  the  teeth  of  the  various 
denominations. 

28.  Study  the  form,  location  and  size  of  the  contact  points 
on  all  of  the  teeth.  B.  par.  195.  Fig.  132  to  136.  B.F. 
pp.  84. 

29.  Make  the  dramngs  and  carvings  of  the  teeth  as  outlined 
in  the  technic  course,  while  studying  their  surface  form. 

HOW  TO   PERFORM   THE   TECHNIC   OPERATIONS 
Materials  and  Instruments  Required 

1.  Note  book  (I.  P.,  loose  leaf.  No.  9108,  for  memoranda 
and  dra"«Tngs). 

2.  Set  of  ivory  or  vegetable  ivory  blocks  (Harper's,  Tenney's 
or  cut  to  order);  or  set  of  soap  or  French  chalk  blocks;  or 
set  of  plaster-of-Paris  blocks. 

3.  Wood  blocks  I  1/4X3/4X3/4  inches. 

4.  Stick  United  States  Express  sealing  wax. 

5.  Half  dozen  smooth  broaches  (round). 

6.  Half  round,  lo-inch  file,  bastard  cut,  medium  coarse. 

7.  Bunsen  burner  and  tubing,  or  alcohol  lamp. 

8.  Small  bench  \dse. 

9.  Mechanical  saw  frame,  12  saws. 
10.  Wax  spatula. 


HOW   TO    PERFORM   THE    TECHNIC    OPERATIONS  Q 

11.  Plaster  bowl   and   spatula. 

12.  Plaster  knife. 

13.  \'ulcanite  chisels. 

14.  \'ulcanite  scrapers. 

15.  Vulcanite  file,  half  round. 

16.  Boley   millimeter  gauge. 

17.  Sheet  fine  sandpaper. 

18.  Xail  brush  and  coarse  cloth. 

19.  Blue  pencil. 

20.  Operative  chisels  and  excavators. 

21.  Ruled  paper  for  prints. 

22.  Mouth  blowpipe. 

23.  Wood  modeling  board  and  modeling  tools. 

The  technic  exercises  in  Dental  Anatomy  to  be  described 
consist  of  outline  and  shaded  drawings  of  the  surface  form  and 
internal  anatomy  of  various  teeth,  modeling  in  clay,  carving 
teeth  in  plaster,  soap,  French  chalk  and  ivory,  the  sawing 
and  filing  of  sections  (showing  the  outline  form  of  the  pulp 
chamber  and  canals)  and  the  making  of  prints  or  silhouettes 
from  these  sections.  All  of  the  exercises  described  may  be 
modified  to  suit  the  needs  of  various  classes,  in  the  judgment 
of  the  teacher.  The  denomination  and  number  of  teeth  to 
be  selected  will  have  to  be  regulated  by  the  amount  of  time 
devoted  to  the  work  and  whether  all  or  only  a  part  of  the 
technical  exercises  here  described  are  to  be  performed.  The 
drawings,  carvings,  sections  and  prints,  where  necessary, 
should  be  annotated  after  Palmer's  notation. 


Palmer's 

Notation 

• 

Permanent  teeth 

8 

7 

6 

5 

4 

3     2     I 

123 

4 

__5^ 

6 

7 

8 

S 

7 

6 

5 

4 

3     2     I 

I     2     3 

4 

5 

6 

7 

"s 

lO  DENTAL   ANATOMY 

Deciduous  teeth 

V  IV    III    II    I     I    I    II    III    IV    V 

V  IV    III    II    I     I    I    II    III    IV    V 

The  drawings  and  carvings  should  be  done  to  Black's 
average  measurements,  natural  size  or  enlarged  as  indicated, 
by  means  of  a  Boley  millimeter  gauge  (Fig.  60). 

Average  Measurements  of  the  Teeth,  Taken  from  Black's 

Dental  Anatomy 

The  lines  of  measurement  are: 

ist.  "Length  over  all":  Length  of  the  tooth  from  the 
cutting  edge,  or  buccal  cusp,  to  the  apex  of  the  root. 

2nd.  "Length  of  crown":  Length  of  the  crown  from  the 
cutting  edge,  or  buccal  cusp,  to  the  gingival  line  on  the  labial 
or  buccal  surface. 

3rd.  "Length  of  root":  Length  of  root  from  the  gingival 
line  on  the  buccal  surface  to  the  apex  of  the  root. 

4th.  "Mesio-distal  diameter  of  crown":  This  is  the  ex- 
tent from  mesial  to  distal  in  the  greatest  diameter,  or  at  the 
points  of  proximate  contact. 

5th.  " Mesio-distal  diameter  of  neck":  This  measurement 
was  made  at  the  gingival  line. 

6th.  "Labio- or  bucco-lingual  diameter":  This  measure- 
ment was  taken  at  the  greatest  diameter  of  the  crown  in  the 
direction  named.  In  the  incisors  it  was  on  the  gingival  ridge. 
In  the  bicuspids  and  molars  it  was  generally  mid-length  of  the 
crown,  but  occasionally  it  was  near  the  gingival  line,  especially 
in  the  upper  second  and  third  molars. 

7th.  "Curvature  of  the  gingival  line":  This  is  the  height 
or  extent  of  the  curve  of  the  gingival  line  toward  the  cutting 
edge,  or  occlusal  surface,  as  it  passes  from  labial  to  lingual, 
measured  on  the  mesial  surface." 


TABLE   OF   MEASUREMENTS 


II 


UPPER  TEETH. 


Table  of 

Measurements 

*    of  the  teeth 

of  man,  given 

in  millimeters 

and  tenths 
of  millimeters. 

UPPER   TEETH 


Length 

Length 

Length 

over 

of 

of 

all. 

crown. 

root. 

Mesio-  Mesio-      Labio-     Curvature 

distal  distal     or  bucco-      of  the 

diam.  diam.       lingual       gingival 

of  crown,  of  neck.      diam.  line. 


Central  Incisor.      22.5        10. c        12.0  9.0  6.3  7.0  30 

Average. 


Lateral  Incisor.       22.0  8.8        130  6.4  4.4  6.0  2.8 

Average. 


Cuspid.  Average 

26.5 

9-5 

17-3 

7.6 

5-2 

8.0 

2-5 

First  Bicuspid. 
Average. 

2C.6 

8.2 

12.4 

7.2 

4-9 

91 

I .  I 

Second  Bicuspid 
Average. 

21.5 

7-5 

14.0 

6.8 

5-3 

8.8 

0.8 

First  Molar. 
Average. 

20.8 

7-7 

13.2 

10.7 

7-5 

II. 8 

2.  2 

Second  Molar. 
Average. 

20.0 

7  ■  2 

130 

9.2 

6.7 

II-5 

1.6 

Third  Molar. 
Average. 

17. 1 

6.3 

II. 4 

8.6 

6.1 

10.6 

0.7 

Note. — This  table  and  the  one  on  the  following  page  are  taken  from  Black's 
Dental  Anatomy. 


12 


DENTAL  ANATOMY 


LOWER  TEETH. 


Table  of 
measurements 

of  the  teeth 
of  man,  given 
in  millimeters 
and  tenths  of 

millimeters. 

LOWER   TEETH 


Length   Length  Length 
over  of  of 

all.       crown.      root. 


Mesio- 
distal 
diam. 


Mesio-      Labio- 
distal     or  bucco- 


Curvature 
of  the 


diam.       lingual  ;    gingival 


Central  Incisor.  |    20.7 
Average. 


of  crown,  of  neck.      diam. 


line. 


S-4 


3-5 


6.0 


2   S 


Lateral  Incisor. 
Average. 

21. 1 

9.6 

12.7 

5-9 

3-8 

6.4 

2-5 

Cuspid.  Average. 

25.6 

10.3 

iS-3 

6.9 

5-2 

7-9 

2.9 

First  Bicuspid. 
Average. 

21.6 

7.8 

14.0 

6:9 

4-7 

7-7 

0.8 

Second  Bicuspid. 
Average. 

22.3 

7-9 

14.4 

7-1 

4.8 

8.0 

0.6 

First  Molar. 
Average. 

21.0 

7-7 

13.2 

II.  2 

8.5 

10.3 

I .  I 

Second  Molar. 
Average. 

19.8 

6.9 

12.9 

10.7 

8.1 

10. 1 

0.  2 

Third  Molar. 
Average. 

1 

18.5 

6.7 

II. 8 

10.7 

8.3 

9.8 

0.  2 

Drawings 

I.  Outline  the  labial  surface  of  the  crown  and  root  of 

1  I  three  times  enlarged,  according  to  Black's  measurements, 

showing  labial  grooves,  curvature  of  cervical  line  (gingival 

line  of  Black),  shape  of  mesio-  and  disto-incisal  angles.     The 

root  is  conical  in  shape  and  the  labial  surface  of  the  crown 

Note. — The  original  drawings  for  the  illustrations  in  this  section  were  made 
by  student  W.  G.  Pieck,  class  of  19x5,  Ohio  College  of  Dental  Surgery. 


DRAWINGS 


13 


irregularly  square  or  trapezoidal.  If  the  bases  of  a  pyramid 
and  a  trapezoid  arc  placed  together,  as  in  Fig.  7,  the  dia- 
gram may  be  made  within. 

2.  Outline  the  mesial  or  distal  surface  of  the  crown  and 


Fig.  7. — Right  upper  central  in- 
cisor. Labial  surface.  A,  labial 
grooves;  B,  curvature  of  cervical 
line;  C,  mesio  and  disto-incisal  angles. 


Fig.  8. — Upper  central 
incisor.  Mesial  surface. 
A ,  Cervical  line. 


root  of  _1_  three  times  enlarged,  showing  curvature  of  cervical 
line  (gingival  line  of  Black).  The  proximal  surfaces  of  the 
crown  are  wedge  shape.  Draw  a  pyramid  and  a  wedge 
placed  base  to  base,  Fig.  8,  and  outline  the  tooth  within. 

Note. — All  of   the  illustrations  in  this  section  are  about  three  diameters  with 
the  exception  of  figures  iS,  19,  23,  24,  30,  31,  32,  ^s,  34- 


14 


DENTAL  ANATOMY 


3.  Draw  and  shade  a  central  incisor  three  times  enlarged 
(Fig.  9). 

4.  Outline  the  labial  surface  of  the  crown  and  root  of 


Fig.  9. — Right  upper 
central  incisor.  Labial 
surface. 


A-. 


h 


3J 


/ 

i 
i 

\\ 

t 
I 
I 

1 

1-; 

.0 


.^ 


.;-A' 


Fig.  10. — Right  upper  cuspid.  La- 
bial surface.  A,  Disto-incisal  angle; 
A^,  mesio  incisal  angles;  B,  labial 
grooves;  C,  cervical  line. 


3  I  enlarged  three  times,  in  the  same  figure  as  indicated  in  No. 
I,  showing  the  location  of  the  mesio-  and  disto-incisal  angles, 
labial  grooves, 


curvature  of  cervical  line   (gingival  line  of 


Black)  (Fig.  10). 


DRAWINGS 


15 


5.  Draw  and  shade  an  upper  cuspid  (Fig.  11). 

6.  Outline  the  buccal  surface  of  the  crown  and  roots  of  _4j, 
enlarged  three  times,  in  the  same  figure  as  before  used,  show- 
ing curvature  of  the  cervical  line  (Broomell),  location  of  angles, 
location  of  point  of  cusp  to  the  distal  and  the  buccal  grooves 
(Fig.  12). 


Fig.  II. — Right   upper 
cuspid.    Labial  surface. 


U  u 

.-^ 

^<^...\ 

B. 


Fig.  12. — Right  upper  first  bicus- 
pid. Buccal  surface.  A,  Cervical 
line;  B,  mesio-  and  disto-incisal  an- 
gles; C,  point  of  buccal  cusp  to  the 
distal;  D,  buccal  grooves. 


7.  Outline  the  mesial  or  distal  surface  of  _£  showing  two 
roots  and  curvature  of  cervical  line  (Broomell).  The  drawing 
may  be  made  within  a  parallelogram  and  a  square,  i)laccd 
base  to  base.  Fig.  13. 

8.  Draw  and  shade  an  upper  second  bicuspid,  showing  the 
point  of  the  buccal  cu.sp  to  the  mesial  (Fig.  14). 


i6 


DENTAL   ANATOMY 


Fig.  13. — Upper    first    bicuspid. 
Mesial  surface.     A,  Cervical  line. 


Fig.  14. — Right  upper 
second  bicuspid.  Buccal 
surface.     A,  Buccal  cusp. 


^ 


^ 


Fig.  15. — ^Lower  first  bicuspid. 


Mesial  surface. 
C,  cervical  line. 


A,  Buccal  cusp;  B,  lingual  cusp; 


DRAWINGS 


17 


G 

Fig.  16. — Left  upper  first  l)icus- 
pid.  Occlusal  surface.  .1,  Mesial 
marginal  ridge;  B,  distal  marginal 
ridge;  C,  buccal  triangular  ridge; 
D,  E,  triangular  grooves;  F,  cen- 
tral groove;  G,  lingual  triangular 
ridge. 


Fio.  17. — Right  lower  second 
bicuspid.  Occlusal  surface. 
Three  cusps.  A ,  Mesial  marginal 
ridge;  B,  lingual  groove;  C,  distal 
groove; D,  buccal  cusp. 


IMcsial  A  -'.  '  7' 


^--/B 


Fig.  18. — Left  upper  and  lower  first  and  second  bicuspids.  .1,  Points  of  cusps  of 
first  bicuspids  nearer  to  the  distal.  B,  Points  of  cusps  of  second  bicuspids  to  the 
mesial. 


DENTAL   ANATOMY 


9.  Outline  the  mesial  or  distal  surface  of  4  within  a  figure 
as  indicated  in  No.  i  reversed,  showing  relative  size  of  buccal 
and  lingual  cusps  and  curvature  of  cervical  line  (Fig.  15). 

10.  Draw  the  occlusal  surfaces  of  _4_  and  5  ,  three  times 
enlarged,  indicating  the  location  of  the  ridges  and  grooves  by 
initials  on  the  drawing.  Make  the  drawings  within  a  figure 
of  trapezoidal  or  keystone  shape  (Figs.  16  and  17). 


D' 


Fig.  19.^ — Right  upper  first 
molar.  Buccal  surface.  A, 
Buccal  groove;  B,  cervical 
line;  C,  mesio-bucco-occlusal 
angle;  D,  disto-lingual  cusp. 


II. 


Fig.  20. — Right  upper  first  molar.  Oc- 
clusal surface.  A,  Disto-lingual  cusp;  B, 
fifth  cusp;  C,  mesio-buccal  cusp;  D,  disto- 
buccal  cusp;  E,  disto-lingual  angle;  F,  buc- 
cal groove;  G,  mesial  groove;  H,  disto-lingual 
groove;  I,  distal  groove. 


Make  a  drawing  showing  the  location  of  points  of  the 
buccal  cusps  of  |_£,  |_5_  and  1 4  ,  |  5  .  According  to  Black's  Den- 
tal Anatomy  they  are  most  frequently  located  as  follows,  viz. : 

Upper  first  bicuspid,  point  of  the  cusp  to  the  distal. 

Upper  second  bicuspid,  point  of  the  cusp  to  the  mesial. 

Lower  first  bicuspid,  point  of  the  cusp  to  the  distal. 

Lower  second  bicuspid,  point  of  the  cusp  to  the  mesial. 
This  does  not  obtain  in  many  instances  (Fig.  18). 


i)K AW  ixr.s 


19 


71     6---^. 


Fig.  21.— Right  upper  second  molar.  Occlusal  surface.  A,  Disto-lingual  cusp; 
B,  mesio-buccal  angle;  C,  disto-buccal  angle;  D,  disto-lingual  angle;  E,  mesio-lingual 
angle;  F,  buccal  groove;  G,  mesial  groove;  //,  disto-lingual  groove;  I,  distal  groove. 


^. 


'>. 


^ 


1^ 


§}   -f-.A 


^E 


Fig.  22. — Right  upper  third  molar.  Occlusal  surface.  .1,  Disto-lingual  cusp; 
B,  mesio-buccal  angle;  C,  disto-buccal  angle;  D,  disto-hngual  angle;  E,  buccal  groove; 
F,  mesial  groove;  G,  mesio-lingual  cusp;  //,  distal  groove. 


20  DENTAL   ANATOMY 

12.  Outline  a  figure  (Fig.  19)  consisting  of  three  pyramids 
and  a  trapezoid,  placed  base  to  base,  and  draw  the  buccal  as- 
pect of  _6_|  showing  three  roots,  buccal  groove,  curvature  of  the 
cervical  line  and  location  of  the  mesio-  and  disto-bucco-oc- 
clusal  angles. 

13.  The  shape  of  the  occlusal  surfaces  of  _6,  _7,  _8_is  irregu- 
larly rhombic  (Figs.  20, 21, 22).  Draw  three  such  figures  and 
outline  the  occlusal  surface  of  _6.  _7,  _8_  one  in  each,  showing 
differences  in  general  shape  of  the  surfaces  of  the  three,  the 


Fig.  23. — The  molar  triangle.  Right  upper  first,  second  and  third  molars.  A 
Entrance  to  mesio-buccal  canal;  B,  entrance  to  disto-buccal  canal;  C,  entrance  to 
lingual  canal. 


difference  in  size  of  the  disto-lingual  lobe,  location  of  the 
fifth  cusp  on  _6_  and  shape  of  the  angles.  Indicate  by  letters 
the  ridges,  fossae,   lobes   and  grooves. 

14.  The  entrance  to  the  canals  on  the  floor  of  the  pulp 
chambers  of  upper  molars  is  situated  at  the  corners  of  an 
imaginary  triangle  known  as  the  Molar  Triangle  (Fig.  23). 
Draw  three  triangles,  one  to  represent  each  upper  molar,  right 
side,  showing  the  difference  in  the  shape  and  size  of  the  tri- 
angles, due  to  diminution  in  the  size  of  the  teeth  and  change  of 
location  of  the  disto-buccal  canal.  Indicate  by  letters  on  the 
drawings  the  location  of  each  individual  canal. 

15.  Draw  three  cubical  figures  and  place  the  mesial  and 
distal  roots  of  a  lower  molar  at  their  bases  (Fig.  24).     Indicate 


DRAWINGS 


21 


by  letters  the  location  of  the  surfaces,  margins,  line  and  point 
angles  of  a  lower  molar. 

1 6.  Draw  and  shade  the  buccal  surface  of  |  6  and  |  7  ,  show- 
ing crown  and  roots  (Figs.  25  and  26). 

17.  Draw  and  shade  the  mesial  surface  of  crown  and  roots 
of  6   (Fig.  27). 


Fig.  24. — Diagrammatic  drawing  to  show  the  surfaces  and  line  and  point  angles 
on  lower  molars. 

First  Diagram. — A,  Mesial  surface;  B,  buccal  surface;  C,  occlusal  surface. 

Second  Diagram. — Line  angles.  A ,  Mesio-lingual  angle;  B,  octiuso-lingual  angle; 
C,  disto-occlusal  angle;  D,  bucco-occlusal  angle;  E,  mesio-occlusal  angle;  F,  disto- 
buccal  angle;  G,  H,  gingival  line. 

Third  Diagram. — Poi7it  angles.  A,  Mesio-linguo-occlusal;  B,  mesio-bucco- 
occlusal;  C,  Disto-linguo-occlusal;  D,  dislo-bucco-occlusal;  E,  disto-bucco-gingival; 
F,  mesio-bucco-gingival;  G,  mcsio-Hnguo-gingival  point  angles. 

18.  Draw  a  trapezoidal  figure,  Fig.  28,  and  outline  occlusal 
surface  of  I  (i  ,  indicating  location  of  the  ridges,  grooves  andlobes. 

19.  Draw  a  parallelogram,  Fig.  29,  and  outline  the  oc- 
clusal surface  of  7  |,  indicating  the  location  of  the  ridges, 
grooves  and  lobes. 


22 


DENTAL   ANATOMY 


Fig.  25. — ^Left    lower    first    molar. 
Buccal  surface. 


Fig.  26. — ^Left  lower  second  molar. 
Buccal  surface. 


W 


16 


Fig.  27. — ^Left  lower  first  molar.     Mesial  surface. 


DRAWINGS 


23 


20.  Draw  the  teeth  of  the  upper  and  lower  jaw  in  occlu- 
sion, showing  correct  curvature  of  the  Hne  of  occlusion,  with 
its  lowest  point  at  the  proper  location,  natural  size  (Fig.  30). 


^ 


'i. 


f6 


^ 


Q> 


^ 


Fig.  28. — ^Left  lower  first  molar. 
Occlusal  surface.  A,  Mesio-buccal  tri- 
angular ridge;  B,  disto-buccal  triangu- 
lar ridge;  C,  distal  triangular  ridge;  D, 
disto-lingual  triangular  ridge;  E,  mesio- 
lingual  triangular  ridge;  F,  mesial  groove; 
G,  mesio-buccal  groove;  H,  disto-buccal 
groove;  /,  distal  groove;  /,  lingual  groove. 


^.■i 


Fig.  29. — Right  lower  second 
molar.  Occlusal  surface.  A, 
Mesio-lingual  lobe;  B,  disto-lin- 
gual lobe;  C,  disto-buccal  lobe; 
D,  mesio-buccal  lobe;  E,  mesial 
groove;  F,  lingual  groove; G,  distal 
groove;  H,  buccal  groove. 


Fig.   30. — Occlusion  of  the  teeth  of  the  left  side. 


21.  Make  a  drawing,  side  view,  showing  the  proper  inclina- 
tion of  the  upper  and  lower  anterior  teeth  (Fig.  31).     The 


24 


DENTAL   ANATOMY 


uppers  have  a  labial  inclination,  the  lowers  have  a  slight 
labial  inclination  or  are  occasionally  perpendicular. 


L^-- 


FiG.  31. — Inclination  of  the  an- 
terior teeth.     Side  view. 


Fig.  32. — Mesial    incUnation    of 
the  upper  central  incisors. 


2  2.  Make  a  drawing,  labial  view,  showing  mesial  inclina- 
tion of  these  teeth  (Fig.  32). 


Fig.  2i3- — Diagrammatic  drawing  showing  buccal  inclination  of  the  upper  molars 
and  lingual  inclination  of  the  lower  molars. 

23.  Make  a  drawing,  mesial  view,  showing  general  buccal 
inclination  of  the  upper  bicuspids  and  molars  and  general 


MODELING   IN    CLAY 


25 


lingual  inclination  of  the  lower  teeth  of  the  same  denomina- 
tion (Fig.  ss)- 

24.  ]\Iake  a  drawing  of  a  longitudinal  section  of  a  central 
incisor,  showing  the  enamel,  dentin,  cementum  and  pulp 
(Fig.  34). 


B--J 


Fig.  34. — Upper  central  incisor.     Proximal  surface.     A,  Enamel;  B,  dentin;  C 
cementum;  D,  pulp.     (Diagrammatic.) 


Modeling  in  Clay 

The  teeth  are  to  be  modeled  to  Black's  measurements, 
enlarged  li\'e  times.  The  rough  molding  to  form  is  first 
done  on  the  modeling  board  with  the  hands,  when  the  finer 


26  DENTAL   ANATOMY 

details  are  then  brought  out  by  means  of  the  modeling  tools. 
A  natural  tooth  in  front  of  the  student  serves  as  a  guide. 

Carving  Teeth  in  Plaster 

The  denomination  of  the  teeth  and  the  number  to  be 
carved  will  be  regulated  by  the  time  at  the  disposal  of  the  stu- 
dent, in  the  discretion  of  the  teacher.  The  technic  of  carving 
is  practically  the  same  as  that  described  for  ivory  teeth 
and  the  student  is  referred  to  that  section  (page  27).  The 
teeth  are  to  be  carved  from  plaster  blocks  to  Black's  average 
measurements,  multiplied  five  times.  The  entire  root  should 
be  carved.  These  teeth  may  be  used  later  for  technic  work 
in  cavity  preparation. 

Carving  Teeth  in  Soap 

The  best  soap  for  the  purpose  is  Procter  and  Gamble's  Ivory 
soap.  This  should  be  cut  in  blocks  of  proper  dimensions, 
and  laid  out  for  hardening  or  seasoning  for  two  weeks  previous 
to  the  carving,  otherwise  it  is  too  soft. 

Carve  all  the  teeth  natural  size,  upper  and  lower  of  one 
side.  The  cuttings  are  made  with  a  knife  and  wax  spatula, 
the  finer  carving  being  done  with  the  excavator  or  small  chisel. 
The  final  polish  may  be  put  on  by  gently  rubbing  with  the 
finger.  The  technic  is  the  same  as  given  under  "Carving  in 
Ivory,"  except  that  the  cuttings  are  done  with  a  knife,  wax 
spatula,  chisel  and  excavator. 

•  Carving  Teeth  in  French  Chalk 

French  chalk. — Synonyms,  Soap-stone,  Talc  Steatite. 
— Chemical  composition,  magnesium  silicate. 


CARVING   TEETH    IN    IVORY  27 

Excellent  carvings  may  be  made  from  this  material,  which 
is  of  an  olive-green,  grayish  or  white  color  and  easily  obtained 
from  drug-suj)ply  houses.  The  white  variety  is  best  for  this 
purpose.  It  is  readily  sawed  into  blocks  of  convenient  size 
and  carved  according  to  the  technic  given  for  carving 
in  ivory.  Its  cutting  consistence  is  much  softer  than  ivory 
and  harder  than  soap.  The  same  instruments  are  used,  the 
final  polish  being  put  on  by  rubbing  with  a  smooth  cloth. 

Carving  Teeth  in  Ivory 

I\-ory  or  bone  blocks  may  be  obtained  for  this  purpose 
from  the  S.  S.  White  Dental  Mfg.  Co.,  the  Wenker  Dental 
Mfg.  Co.  and  Armour  &  Sons.  Dr.  Harper's,  a  set  of  six 
blocks,  and  Dr.  Tenney's,  a  set  of  four,  are  also  available. 
Vegetable  ivory  blocks  are  used  as  a  substitute  in  some 
schools.  They  are  not  so  hard  as  the  ivory  or  bone  block, 
and  may  be  still  further  softened  by  saturation  in  water. 
The  teeth  to  be  carved  are  to  be  decided  by  the  teacher. 

Directions  for  Carving 

Select  a  well-formed  natural  tooth.  This  is  to  serve  only 
as  a  guide  in  the  carving  and  not  to  be  duplicated.  The 
ivory  carving  is  made  to  Black's  measurements,  with  the 
millimeter  gauge  and  on  completion  should  be  within  0.5  mm. 
of  Black's  measurements.  For  the  lines  of  measurement,  see 
page  10. 

I.  Central  Incisor. — The  instructions  for  car^•ing  the  cen- 
tral will  serve  for  any  of  the  anterior  teeth. 

(a)  With  a  blue  pencil  or  ink,  mark  on  the  block  the  loca- 
tion, taken  by  means  of  the  Boley  gauge,  of  the  future  cou- 
tact  points,  allowing  0.5  mm.  excess  for  finishing  down. 


28 


DENTAL   ANATOMY 


-IZmm 


^■^ 


^■^ 


1— 9ffim  — 

t- 

^ 


/ 

s 

o 

-S.^Tmn 
/ 

/ 

Fig.  35. — Marking  and 
sawing  the  block  to  the  future 
contact  points  and  giving  it 
the  general  slope  of  the  cutting 
edge.  Labial  surface.  The 
illustrations  are  not  to  scale. 


Fig.  36. — Outlining  the 
cutting  edge;  measuring  the 
length  of  the  crown  and  the 
mesio-distal  diameter  at  the 
neck;  outlining  the  convexity 
of  the  proximal  surfaces,  fiUng 
to  these  marks  and  blocking 
out  the  root. 


Fig.  37. — Taking  the 
measurement  for  the 
greatest  labio-lingual  diam- 
eter and  sawing  the  block 
to  this  dimension.  Proxi- 
mal surface. 


Fig.  38. — Block  gradually 
assuming  proper  form. 


DIRECTIONS    FOR    CARVING 


29 


(b)  vSaw  the  l)lock  down  to  these  points. 

(c)  With  the  blue  i)encil,  outUne  the  future  culling  edge 


Fig.  39. — Filing  the 
block  on  the  mesial  and 
distal  sides  to  proper  cur- 
vature of  the  labial  and  lin- 
gual surfaces. 


Fig.  40. — Outlining  the  curvature  of  the  cer- 
vical hne.     Labial  and  proximal  view. 


with  its  proper  slope  toward  the  disto-incisal  angle,  and  with 
the  saw  and  vulcanite  file  trim  the  block  nearly  to  this  line, 
allowing  0.5  mm.  excess  for  finishing  (Fig.  35). 


F'lG.  41. — Carving  complete.     Labial  and  lingual  view. 

(d)  With  the  millimeter  gauge,  measure  the  lengtJi  of  the 
crown  from  the  cutting  edge  to  the  future  cervical  line  on  the 

Note. — The  drawings  illustrating  the  method  of  carving  were  made  by  student 
E.  W.  Nicdcrhofer,  class  of  1915,  Ohio  College  of  Dental  Surgery. 


30  DENTAL   ANATOMY 

labial  surface,  and  mark  the  location  of  the  cervical  line  (gin- 
gival, Black)  with  the  pencil. 

(e)  Mark  the  location,  taken  by  means  of  the  Boley  gauge, 
of  the  future  mesio-distal  diameter  of  the  neck  of  the  tooth. 
Then  outline  the  convexity  of  the  mesial  and  distal  surfaces  by 
drawing  a  line  from  the  contact  points  to  these  marks. 

(f)  With  the  file  trim  the  blocks  on  the  mesial  and  distal 
sides  nearly  to  the  marks  made  in  "e, "  giving  these  sides  the 
proper  convexity,  the  distal  side  being  more  convex.  The 
cuttings  may  be  carried  a  distance  of  half  way  up  the  future 
root  of  the  tooth  (Fig.  36). 

(g)  With  the  Boley  gauge  take  the  measurement  for  the 


Fig.  42. — Carvings  in  ivory. 

greatest  lahio-lingual  diameter,  which  will  be  at  the  gingival 
ridge,  and  mark  it  on  the  mesial  and  distal  sides  of  the  block 
(Figs.  37  and  38). 

(h)  Now,  holding  the  block  on  its  mesial  or  distal  side,  out- 
line with  the  pencil  the  curvature  of  the  labial  and  lingual  sur- 
face from  the  cutting  edge  to  the  cervical  line. 

(i)  File  to  shape,  carrying  the  labial  and  hngual  cuttings  a 
distance  of  half  way  up  the  future  root.  The  apical  half  or 
third  of  the  root  is  not  carved,  leaving  the  end  of  the  block 
untouched  (Fig.  39). 

(j)  To  outline  the  curvature  of  the  cervical  line,  find  the 
proper  measurement  from  the  "Table  of  Measurements"  and 
mark  the  length  of  curvature  by  means  of  the  millimeter  gauge 


SAWING   AND   FILING    SECTIONS  3 1 

on  the  labial  surface;  then  draw  a  straight  line  from  this  point 
to  the  mesial  and  distal  surfaces,  which  will  then  give  the 
extent  of  the  curvature  (Fig  40). 

(k)  Bring  all  the  cuttings  down  to  proper  measurement, 
and  do  the  finer  carving  with  the  file,  scraper  and  small 
chisels  and  excavators,  representing  the  marginal  and  gingival 
ridges,  grooves,  cervical  line  and  all  other  points  (Fig.  41). 

(i)  Finish  with  sandpaper  of  increasing  fineness,  and  then 
with  pumice  and  whiting  on  the  lathe  (Fig.  42). 

2.  Bicuspid  and  Molar. — Practically  the  same  directions 
are  followed.  First  mark  the  contact  points  and  saw  or  trim 
not  quite  to  them.  Repeat  the  same  procedure  for  the  bucco- 
lingual  diameter.  Then  measure  for  the  length  of  the  crown 
on  the  buccal,  lingual,  mesial  and  distal  sides,  after  which 
outline  with  the  pencil  the  proper  contours  and  saw  or  file  to 
them,  finally  extending  the  cuttings  the  desired  length  and 
shape.  Then  complete  the  surface  markings,  such  as  ridges, 
grooves  and  cusps,  as  well  as  the  cervical  line,  with  the 
scraper  and  chisels  and  excavators,  completing  the  work  with 
sandpaper,  pumice  and  whiting. 

If  desired  and  time  permits,  the  teeth  of  the  upper  and  lower  jaw,  right  or  left 
side,  may  be  carved  and  then  mounted  in  occlusion  on  hard  or  soft  rubber  jaws  as 
suggested  by  Dr.  A.  E.  Webster.  If  this  is  done,  all  the  teeth  should  be  modeled 
after  a  definite  type,  as  sanguine,  bilious,  nervous  or  lymphatic.  They  may  then 
be  later  used  for  the  technic  exercises  in  cavity  preparation. 

Sawing  and  Filing  Sections 

The  object  of  cutting  sections  is  to  give  the  student 
familiarity  with  the  cutting  consistence  of  natural  tooth  struc- 
ture, to  familiarize  him  with  the  thickness  of  enamel,  dentin 
and  cementum,  together  with  their  relations  to  each  other, 
and  to  expose  the  pulp  chamber  and  canals  for  purposes  of 
study. 


32 


DENTAL    ANATOMY 


1.  Longitudinal  Sections. — Make  one  section  by  means  of 
the  file  from  the  labial,  buccal  or  lingual,  and  one  from  the 
mesial  or  distal  aspect  of  the  teeth  selected  by  the  teacher. 

2.  Transverse  Sections. — Make  by  means  of  the  saw  a 
transverse  section  at  the  cervical  line  and  another  at  mid-root 
of  the  upper  and  lower  teeth  selected. 

Directions. — (i)  For  the  Longitudinal  Sections. — (a)  Fix 
the  tooth  on  the  wood  block  by  means  of  melted  sealing  wax 


Fig.  43. — ^Longitudinal  section  of 
the  upper  central  incisor,  labial  as- 
pect, mounted  and  annotated. 


Fig.  44. — ^Longitudinal  section  of 
the  lower  central  incisor,  mesial  as- 
pect, mounted  and  annotated. 


and  a  wax  spatula.  For  sections  showing  the  labial  or  buccal 
aspect  of  the  chamber  and  canals,  mount  the  tooth  with  the 
lingual  surface  facing  up.  For  those  showing  the  mesial  or 
distal  aspect,  mount  the  opposite  surface  facing  up.  (b)  Fix 
the  block  securely  in  the  bench  vise  and  file  longitudinally  at 
an  angle  of  45  degrees  until  the  pulp  chamber  is  exposed,  (c) 
Then  insert  a  smooth  broach  into  the  chamber  and  carry  it  the 
full  length  of  the  canal  through  the  apical  foramen.     File  until 


TRANSVE'RSE    SECTIONS 


^3 


tlu'  l)r()ach  is  exposed  full  length.  Then,  rcnioxing  the  Ijroach, 
clear  out  the  contents  of  the  chamber  and  canals  and  render 
clean  and  smooth  so  that  a  good  clear-cut  print  may  be  made 
later  (Figs.  43  and  44). 

(2)  Transverse  Sections. — (a)  Mount  the  tooth  longitudi- 
nally on  the  block  by  means  of  sealing  wax.  (b)  Fix  in  the 
\'ise,  and,  with  the  saw,  make  a  transverse  section  at  the  neck 
and  another  at  mid-root,  thus  cutting  the  tooth  into  three 


Fig.  45. — Tooth  mounted  on  a  wood 
block  and  sawed  into  three  sections. 


Fig.  46. — Gingival  section  of  an 
upper  central  incisor,  mounted  and 
annotated. 


sections,  (c)  Clear  out  the  contents  of  the  chamber  and 
canals  with  broacches  and  excavators,  rendering  the  margins 
distinct  and  clear  for  making  prints  later  (Figs.  45,  46,  47  and 
48). 

(d)  MoiDiting  the  Sections. — Mount  the  section  perma- 
nently on  the  block  by  covering  the  face  of  the  block  with 
melted  sealing  wax,  building  it  up  so  as  to  ele\'ate  the  section 
from  the  block  if  so  desired.     Sm.ooth  the  wax  with  a  spatula 
3 


34 


DENTAL   ANATOMY 


and  put  on  a  high,  smooth  finish  with  a  mouth  blowpipe. 
The  margins  of  the  section  should  extend  shghtly  above  the 
level  of  the  sealing  wax  so  as  not  to  interfere  later  with  the 
making  of  a  good  print. 

(e)  Cutting  the  Relief  Line. — With  a  small  wheel  bur  or 
chisel  cut  a  relief  line  on  the  longitudinal  section  at  the 
junction  of  the  enamel  and  dentin,   removing  the  stratum 


mmmm 


mm 


Fig.  47- — Mid-root  section  of  an  upper  Fig.  48. — Apical  third  section  of  the 

central  incisor,  mounted  and  annotated.  upper  central  incisor. 

granulosum  and  thus  bringing  out  the  thickness  of  the  enamel 

cap. 

(f)  Finishing. — Smooth  the  entire  exposed  surface  of  all 
the  sections  with  fine  sandpaper. 

(g)  Labeling  or  Annotating  the  Sections. — For  the  upper 
longitudinal  sections,  mark  the  notation,  as  _1_,  _2_,  _3_  in  the 
upper  left-hand  corner  and  the  aspect  presenting  to  view  as  La., 
Li.  Bu.,  in  the  xx^^ex  right-hand  corner  (Fig.  43).  For  thelowers 
place  them  in  the  lower  left-  and  right-hand  corners  respec- 


A   METHOD   OF   MOUNTING   SECTIONS 


35 


ir  y  V 


5      /  5       '5 
A         B    ,     C 


i  e  ft  f  ^Tf 

8U         A    /    B  C         M         > 


M          A    ,/   B 

*i 

w 

.  7u 

''7 
^   A 

7 
^    B 

7 

.  c 

i'U 

f 

T 

M 

f 

/8 
A 

T 

8 

B 

f 

sag 

nil                 A                   u 

■8 

8 

BU          A            o 

L- 

c 

Fig.  49. — A  method  of  mounting  and  annotating  a  box  of  Qfty-six  longitudinal 
and  transverse  sections.  The  face  of  the  wood  block  is  covered  with  seaUng  wax, 
which  is  modeled  to  form  with  a  wax  spatula  and  polished  by  heating  with  a  mouth 
blowpipe. 


36  DENTAL   ANATOMY 

tively  (Fig.  44).  In  this  way  the  denomination  of  the  tooth 
and  the  aspect  presenting  to  view  may  be  seen  at  a  glance. 
For  the  transverse  sections  the  same  plan  is  followed  in 
regard  to  the  denomination  of  the  tooth.  Also  label  the 
block  in  the  upper  or  lower  right-hand  corner,  depending  on 
whether  the  tooth  is  upper  or  lower,  A,  B,  or  C,  thus  indicating 
whether  it  is  the  crown,  mid-root  or  apical  section;  A  repre- 
senting the  crown,  B  the  mid-root,  and  C  the  apical  portion 
(Figs.  46,  47,  48). 

Making  Prints  or  Silhouettes 

Object. — To  further  impress  upon  the  student's  mind 
the  size,  location  and  shape  of  the  pulp  chamber  and  canals, 
the  outline  form  of  the  tooth  and  the  relative  thickness  of 
the  enamel  and  dentin. 

Directions. — ^The  prints  are  made  on  ruled  paper,  as  iii 
the  illustration.  Fig.  50,  from  the  sections  already  made. 
The  face  of  the  section  must  be  perfectly  smooth  and  the 
enamel  line  and  chamber  and  canal  margins  clearly  cut,  if 
good  prints  are  desired. 

(a)  Ink  the  surface  of  the  section  by  bringing  it  in  contact 
with  the  ink  pad.     Avoid  too  much  ink. 

(b)  Stamp  the  section  firmly  in  contact  with  the  note 
paper,  and  hold  steadily  for  a  few  moments  to  allow  the  ink 
to  take  hold  of  the  paper.  In  curved  sections  great  care  is 
necessary  to  bring  every  portion  of  the  section  in  contact 
with  the  paper.  Several  thicknesses  of  the  paper  may  be 
held  in  the  palm  of  the  left  hand  while  stamping  with  the 
right  hand;  or  laying  the  paper  on  a  soft  rubber  pad  of  about 
1/4  inch  in  thickness  and  carefully  rotating  the  section 
longitudinally  is  a  valuable  procedure  in  these  cases. 

(c)  Annotate  the  prints  in  the  same  manner  as  described 
for  the  sections  (Fig.  50). 


MAKING  PRINTS 


37 


1 

E 

t 

M  EStAL 

fl, 

s 

SuCCAL 

a.T./V&?  VAi. 

0 

0 

0 

MiDOuRcoT 

.^ 

• 

1^ 

J 

V 

J 

Apex 

Fig.  50. — A  page  from  a  book  of  prints,  showing  longitudinal  and  transverse 
views  of  the  pulp-chambers  and  canals  of  the  upper  second  molar. 


38  DENTAL   ANATOMY 

REVIEW   QUIZ 

1.  Give  the  definition  of  a  human  tooth. 

Answer :  One  of  thirty- two  speciahzed  organs,  situated 
in  the  alveolar  process  of  the  upper  and  lower 
jaws,  designed  for  purposes  of  mastication,  to 
assist  in  articulate  speech  and  to  regulate 
facial  contour, 

2.  Defineangleanddistinguishbetweenlineandpoint  angle. 

3.  Define  fossa  and  give  location  and  names  of  the  fossae 
on  incisors  and  molars. 

4.  Define  lobe  and  distinguish  between  lobe  and  cusp. 

5.  Define  ridge  and  name  the  marginal  ridges  on  incisors, 
cuspids,  bicuspids  and  molars. 

6.  Describe    the   location   of    the   transverse   ridge    on 
bicuspids. 

7.  Describe  the  location  of  the  oblique  ridge  on  molars. 

8.  Describe  the  location  of  the  triangular  ridge  on  bicus- 
pids and  molars. 

9.  On  what  teeth  are  supplemental  ridges  most  frequently 
found? 

10.  Describe  the  location  of  the  developmental  grooves  on 
incisors,  cuspids,  bicuspids  and  molars. 

11.  On  what  teeth  are  supplemental  grooves  most  fre- 
quently found? 

12.  Name  the  sulcate  grooves  on  cuspids,  bicuspids  and 
molars. 

13.  Define  groove,  sulcus,  fossa. 

14.  Name  the  roots  of  upper  bicuspids,  upper  molars  and 
lower  molars. 

15.  Name  the  canals  in  the  same  teeth. 

16.  Distinguish  between  fossa  and  pit. 

17.  Name  the  pits  on  bicuspids. 


REVIEW   QUIZ  39 

1 8.  On  what  part  of  incisors  are  pits   most  frequently 
found? 

19.  Define  axial  plane;  horizontal  plane. 

20.  Give  another  name  for  comua. 

21.  Describe  the  horns  of  the  pulp  in  incisors,  cuspids, 
bicuspids  and  molars. 

22.  What  conditions  regulate  the  size  of  the  cornua^? 

23.  Give  the  derivation  of  the  word  "incisor.'' 

24.  Define  the  term  "  succedaneous"  and  name  the  succe- 
daneous  teeth. 

25.  Name  the  chief  points  of  difference  between  the  upper 
central  and  lateral  incisors. 

26.  Name  the  chief  points  of  difference  between  the  upper 
and  lower  incisors. 

27.  Describe  the  form  of  the  roots  and  root  canals,  on 
section,  of  the  anterior  teeth,  upper  and  lower. 

28.  Describe  the  form  of  the  roots  and  root  canals,    on 
section,  of  the  upper  and  lower  bicuspids. 

29.  Describe  the  form  of  the  roots  and  root  canals,  on 
section,  of  the  upper  and  lower  molars. 

30.  Define  the  term  "cingule"  and  give  its  most  frequent 
location. 

31.  Define  the  term  "axial." 

32.  Name  the  surfaces  of  all  the  teeth. 
T,^.  How  are  surfaces  named? 

34.  Define  proximal  surface. 

35.  Define  median  line. 

36.  Distinguish  between  line  and  plane  of  occlusion. 

37.  Describe   the  difference  in  the  facial  angle   of   the 
Caucasian  and  Negro  or  mixed  races. 

^8.  Is  the  upper  or  lower  arch  the  larger? 
39.  Describe  the  mesio-distal  occlusion  of  the  teeth  be- 
ginning at  the  median  line. 


40  DENTAL   ANATOMY 

40.  With  the  teeth  in  occlusion,  describe  the  relation  of 
the  incisal  edges  of  the  upper  and  lower  anteriors  and  the 
buccal  and  lingual  cusps  of  the  upper  and  lower  bicuspids 
and  molars. 

41.  Define  inclination  of  the  teeth. 

42.  Describe  the  inclination  of  all  the  teeth. 

43.  Describe  the  interproximal  space. 

44.  Describe  the  interproximal  embrasure. 

45.  What  is  the  average  measurement  of  the  arch  in 
inches? 

46.  Give  the  total  measurement  of  all  the  teeth  at  the 
necks. 

47.  What  is  the  average  aggregate  measurement  of  the 
interproximal  spaces? 

48.  Under  normal  conditions,  what  tissues  occupy  the 
interproximal  spaces? 

49.  Give  the  formulae  for  the  permanent  and  temporary 
teeth. 

50.  Write  the  notation  for  the  following  permanent  teeth, 
viz  :  right  upper  central,  left  upper  lateral,  right  lower  cuspid, 
left  lower  first  bicuspid,  right  upper  second  molar,  left  lower 
third  molar. 

51.  What  teeth  are  indicated  by  the  following  notations, 
viz.:|j_,^|,   1|,[3:  5-1,16,  61? 

52.  Write  the  notation  for  all  the  temporary  teeth. 

53.  Define  secondary  dentin  and  tell  where  and  when  it  is 
found. 

54.  Describe  the  pericementimi  and  give  another  name 
for  it. 

55.  Define  rugae. 

56.  Define  gingiva  and  give  plural. 

57.  Define  frenum  labium  superioris,  frenum  labium 
inferioris  and  frenum  linguae. 


CHAPTER  II 
INSTRUMENTS  AND  APPLIANCES 

In  order  that  the  student  may  be  enabled  to  grasp  the 
subject  matter  of  the  following  chapters,  intelligently  perform 
the  various  technic  operations  to  be  later  outlined,  and 
equip  himself  for  clinical  work  in  his  junior  year,  a  thorough 
knowledge  of  instruments  and  appliances,  their  names  and 
uses,  is  essential.  It  is  necessary  that  he  be  grounded  in  the 
metallurgical  properties  of  steel,  from  which  most  of  these 
instruments  are  made,  know  their  methods  of  construction 
and  practise  the  proper  instrument  grasps,  rests  and  guards. 

The  following  is  intended  only  as  a  brief  review  of  the 
working  properties  of  steel.  It  is  taken  for  granted  it  will 
receive  full  attention  in  the  metallurgical  laboratory. 

STEEL 

Definition. — An  alloy  capable  of  being  hardened,  softened 
and  tempered,  made  by  the  addition  of  a  small  percentage  of 
carbon  to  iron;  melting  point  variously  estimated  at  from 
1500-1600°  C. 

Soft  steel  contains  0.5  per  cent,  or  less  of  carbon.  Hard 
steel  contains  from  0.5  per  cent,  to  1.5  per  cent,  of  carbon. 

Steel  of  an  extreme  degree  of  hardness,  containing  a  large 
percentage  of  carbon,  is  utilized  for  making  dental  cutting 
instruments. 

Hardening  Steel. — Ordinary  steel  may  be  hardened  to  its 
limit  by  heating  to  a  /////  cherry  red  color  and  immediately 
plunging  in  cold  water.     In  this  state  it  is  extremely  brittle. 

41 


42  INSTRUMENTS   AND   APPLIANCES 

The  more  carbon  it  contains,  the  harder  and  more  brittle  it 
becomes. 

Tempering  Steel.^ — By-tempering  steel  is  meant  the  process 
of  rendering  it  softer,  tougher  and  less  brittle.  It  is  ac- 
complished by  heating  to  a  lower  temperature  than  that  used 
for  hardening  steel,  and  then  plunging  in  cold  salt  water, 
slightly  acidulated  water ^  oil  or  mercury.  Oil  gives  a  tougher 
temper  than  water,  while  mercury  gives  an  extreme  degree  of 
toughness.  Hard  steel  is  capable  of  much  more  temper  than 
soft  steel. 

Annealing  Steel. — The  operation  of  reducing  it  to  its 
extreme  degree  of  softness.  This  is  accomplished  by  heating 
to  dull  or  "incipient"  redness  and  cooling  slowly.  A  greater 
degree  of  softness  is  produced  by  covering  with  sand,  plaster 
or  pumice,  thus  excluding  the  atmosphere,  heating  and 
allowing  to  cool  while  so  covered. 

In  the  manufacture  of  dental  instruments,  hard  steel 
(that  containing  a  high  percentage  of  carbon)  of  a  higher  or 
lower  degree  of  temper  is  required,  depending  upon  the  pur- 
pose for  which  the  instrument  is  intended.  The  following 
table  shows  the  approximate  temperatures,  with  the  cor- 
responding colors  produced,  to  which  instrument  steel  is 
carried  in  the  making  of  various  instruments : 

Temperature  Color  Use 

217°  to  232°  C light  yellow enamel  chisels,  burnishers. 

243°  C medium  yellow excavators,  scalers. 

258°  C brown-yellow pluggers. 

266°  C brown-purple saws,  shanks  of  instruments. 

279°    to  299°  C blue spring  temper. 

Technical  Exercises  in  the  Working  of  Steel 

I.  Making  Smooth  Broaches  and  Canal  Explorers.^Cut 

piano  wire  of  the  desired  gauge  to  the  required  length  and 


TECHNICAL   EXERCISES   IN   THE    WORKING    OF    STEEL  43 

file  to  a  point  with  a  long  taper;  or  utilize  old,  worn  pul]) 
canal  cleansers  for  the  same  purpose  by  filing  off  the  barbs 
and  reducing  to  the  desired  size  and  taper.  Remove  file 
marks  and  polish  with  emery  paper.  These  may  be  later 
used  in  the  technic  course  as  canal  explorers  and  dressers. 
The  points  of  those  intended  to  be  used  for  explorers  and  for 
placing  cotton  dressings  in  canals,  where  they  are  to  be  left 
temporarily,  should  be  filed  to  a  sharp  point.  Cotton, 
wrapped  around  a  broach  of  this  kind,  has  a  natural  tendency 
to  come  off.  Those  intended  for  swabbing  and  drying  the 
canals,  where  it  is  desired  to  withdraw  the  cotton  with  the 
broach,  should  have  their  ends  cut  off  square,  with  a  pair 
of  scissors,  when  it  will  be  found  that,  when  wrapped  with 
cotton,  they  will  retain  it  very  readily. 

2.  Making  Hooked  Extractors. — Place  the  point  of  a 
piano  wire  broach  (as  made  in  No.  i)  on  an  anvil.  Lay  the 
sharp  blade  of  a  knife  i/8  inch  from  the  end,  with  the  edge 
of  the  blade  pointing  toward  the  shaft  of  the  broach.  Elevate 
the  shaft  of  the  broach,  when  the  hook  may  be  made  at  either 
a  right,  acute,  or  any  desired  angle,  depending  on  the  degree 
of  elevation  of  the  shaft.  File  the  point  to  the  desired  length 
and  sharpness.     Polish  as  before. 

3.  Exercises  to  Illustrate  Annealing,  Hardening  and 
Tempering : 

(a)  Annealing. — (i)  Place  a  few  smooth  broaches  on  a 
plate  of  iron,  heat  to  *'full  cherry"  redness  and  allow  to  cool 
slowly.  (2)  Cover  a  few  more  with  plaster,  pumice  or  sand, 
heat  to  "full  cherry"  redness  and  allow  to  cool  slowly. 
Note  the  difference  in  result  accomplished  by  the  two  pro- 
cedures. (3)  Heat  the  small  end  of  an  excavator  blank  to 
full  cherry  redness  and  allow  to  cool  slowh'. 

(b)  Hardening. — Coat  an  excavator  blank  with  soap  to 
prevent  overheating  and  burning  out  of  carbon.     Heat  to  full 


44  INSTRUMENTS   AND   APPLIANCES 

cherry  redness  and  plunge  in  cold,  slightly  acidulated  or 
salt  water,  oil  or  mercury. 

(c)  Tempering. — (i)  Heat  the  shank  and  blade-end  of  the 
same  excavator  blank  to  cherry  red  and  plunge  immediately 
in  any  of  the  above  media.  Polish  on  the  lathe  to  remove  the 
oxides,  which  have  accumulated  on  the  surface.  Test  with  a 
file  to  ascertain  if  full  hardness  has  been  produced.  (2)  If 
so,  pass  in  the  flame  again  and  heat  the  blade-end  to  a 
medium  yellow  color;  plunge  immediately  (thus  tempering 
the  blade-end),  after  which  again  polish  to  remove  the  oxides. 
(3)  Place  the  small  end  in  contact  with  a  hammer  to  prevent 
drawing  the  temper  at  the  point,  apply  the  flame  back  of  the 
shank  and  heat  to  a  blue  color  (spring  temper),  immediately 
plunging  in  oil,  thus  tempering  the  shank. 

INSTRUMENTOLOGY 

Parts  of  an  Instrument. — Instruments  may  be  divided 
into  those  intended  to  be  used  by  hand — ^Hand  Instruments — 
and  those  for  use  in  the  dental  engine — ^Engine  Instruments. 
Most  instruments  consist  of  three  parts,  viz.,  (i)  Handle  or 
Shaft ,[{2)  Shank,  and  (3)  Blade  or  Nib.  The  Handle  or  Shaft  is 
that  part  which  is  grasped  by  the  hand  in  using  (Fig.  51).  The 
Blade  is  the  cutting  part  of  cutting  instruments,  while  the 
working  part  of  pluggers  is  known  as  the  Nib.  The  Shank  is 
the  part  connecting  the  handle  or  shaft  with  the  blade  or  nib. 
The  taper  from  handle  to  blade  is  to  impart  proper  balance  to 
the  instrument  and  to  give  shape,  lightness  of  touch  and  deli- 
cacy of  manipulation.  Most  modern  hand  instruments  in 
dentistry  are  intended  for  delicate  manipulation  and  require 
small  handles,  while  some  others  are  used  for  heavier  work  and 
should  have  larger  handles.  The  rule  in  selecting  handles  is, 
the  more  dehcate  the  work  intended  to  be  performed  the 


INSTRUMENT   HANDLES 


45 


smaller  the  handle  and  vice  versa.  Handles,  whenever 
possible,  should  he  of  steel  on  account  of  convenience  in 
sterihzihg  (Fig.  52). 


9^ 


n 


1^ 


Fig.  51. — \'ulcaniti- instrument  handles.       Fig.  52. — Steel    cone-socket    instru- 
ment handles. 

Angles  in  Shanks. — The  shank  of  an  instrument  ma}-  be 
straight  or  bent  at  various  angles  for  better  balancing  of  the 
instrument   and   to    carry  the  blade   or  working   part  into 


46  INSTRUMENTS   AND   APPLIANCES 

inaccessible  places.  Dr.  Black  has  classified  instruments 
into  (i)  Mon-angle,  (2)  Bin-angle,  (3)  Triple-angle,  and  (4) 
Quadrangle,  depending  on  whether  they  have  one,  two,  three, 
or  four  angles  in  the  shank. 

Contra -angles. — For  better  balancing  and  in  order  to 
bring  the  blade  as  near  as  possible  in  a  direct  line  with  the 
long  axis  of  the  shaft,  the  shanks  of  instruments  are  also 
contra-angled.  This  variety  of  instrument  has  a  less  tendency 
to  turn  in  the  hand  when  being  used,  and  consequently  will 
do  better  work  with  less  strain  on  the  operator.  Contra- 
angle  instruments  are  divided  into  (i)  Bin-angle  Contra- 
angles,  (2)  Triple-angle  Contra-angles,  and  (3)  Quadrangle 
Contra-angles,  depending  on  whether  there  are  two,  three  or 
four  bends  in  the  shank  of  the  instrument.  A  well-balanced 
instrument  should  be  so  contra-angled  as  to  bring  its  working 
point  within  2  millimeters  of  the  long  axis  of  its  shaft.  For 
example  of  angles  in  instrument  shanks  see  Fig.  61. 

Instrument  Grasps. — As  soon  as  the  student  begins  to 
handle  instruments,  ,he  should  learn  the  proper  grasps. 
Proper  instrument  grasps  lead  to  proficiency  in  the  per- 
formance of  dental  operations,  and  should  be  thoroughly 
studied  and  practised  if  the  best  results  are  to  be  obtained. 
Carelessness  in  this  respect  will  lead  to  bad  habits  which  may 
cling  throughout  life.  The  three  principal  grasps  are  (i) 
The  Pen  Grasp,  (2)  The  Inverted  Pen  Grasp,  and  (3)  The 
Palm  and  Thumb  Grasp.  There  are  other  grasps  which  are 
occasionally  used,  but  as  they  are  of  minor  importance  they 
will  not  be  described. 

(i)  The  Pen  Grasp  is  most  frequently  used  and  is  the  one 
intended  for  great  delicacy  of  touch.  The  instrument  is  held, 
as  the  name  indicates,  like  a  pen  in  writing,  except  that  the 
shank  should  be  in  direct  contact  with  the  pulps  of  the  thumb 
and  first  and  second  fingers.     With  practice,  this  gives  great 


INSTRUMENT   GRASPS 


47 


power,  facility,  delicacy  and  range  of  movement.  The  second 
finger  should  not  be  allowed  to  crawl  under  the  shank  toward 
the  iinger-joint,  as  seen  with  some  operators,  thus  limiting 
the  range  of  movement  and  lessening  the  power  of  the  thrust 
(Fig-  53)-     A  modification  of  the  pen  grasp  is  seen  in  P'ig. 


Fig.  53. — The  pen  grasp,  the  rest  and  the  guard. 

2  20,  where  the  instrument  is  held  between  the  balls  of  the 
thumb  and  first  finger. 

(2)  The  Inverted  Pen  Grasp  is  similar  to  the  pen  grasp 
except  that  the  position  of  the  instrument  is  reversed,  so 
that  the  working  part  points  toward,  instead  of  away  from, 
the  hand.  This  grasp  is  only  used  occasionally.  Fig.  219 
shows  a  modification  of  the  inverted  pen  grasp.     The  position 


48 


INSTRUMENTS   AND    APPLIANCES 


of  the  second  finger  is  incorrect,  as  the  instrument  should  lie 
against  the  pulp  of  the  second  finger. 

(3)  The  Palm  and  Thumb  Grasp  is  the  grasp  of  power,  and 
is  accomplished  by  placing  the  instrument  in  a  position  similar 
to  the  one  utilized  in  whittling  a  piece  of  wood,  the  handle, 
resting  in  the  palm  of  the  hand,  being  grasped  by  the  four  fin- 
gers, while  the  thumb  rests  on  some  adjoining  surface  (Fig.  54), 

The  strength  of  the  thrust  is  largely  influenced  by  the 


Fig.  54. — The  palm  and  thumb  grasp. 

proper  use  of  the  grasp  and  may  be  markedly  increased  by 
frequent  exercise. 

Rests  and  Guards. — While  maintaining  the  proper  in- 
strument grasps,  it  becomes  necessary  to  steady  the  right 
hand  during  the  performance  of  the  operation,  in  order  that 
the  instrument  may  be  securely  held  to  its  work  without 
slipping.  In  the  case  of  the  pen  and  inverted  pen  grasps 
this  is  accomplished  by  resting  the  fourth  or  fifth  or  both 
fingers  on  the  tooth  operated  upon,  or  on  some  adjoining 


RESTS    AND    GUARDS 


49 


tooth,  or  surface.  The  steadying  of  the  hand  is  accompHshed, 
when  the  palm  and  thumb  grasp  is  assumed,  by  means  of 
the  thumb,  resting  it  on  some  convenient  location.  This 
position  of  the  fingers  or  the  thumb  is  known  as  The  Rest 
(Fig.  53).  The  Guard  is  the  position  assumed  by  the  thumb 
and  forefinger  of  the  left  hand  to  steady  the  parts  operated 
upon  and  protect  them  from  injury,  in  case  of  accidental 
slipi)ing  of  the  instrument  (see  Fig.  53).     The  thumb  is  placed 


Fig.  55. — The  guard. 

on  one  side  of  the  tooth  operated  upon  and  the  forefinger  on 
the  other,  the  position  being  reversed,  depending  on  the 
location  of  the  operation  (Fig.  55).  The  practice  of  the 
proper  rests  and  guards  is  important  and  should  receive 
close  attention  in  the  technic  laboratory  at  the  same  time 
that  the  study  of  instrument  grasps  is  begun. 

The  Metric  System  of  Measurement 

Before  taking  up  the  study  of  instrument  forms  and  their 
manufacture,  it  is  necessary  for  the  student  to  ha\e  a  knowl- 
4 


50  INSTRUMENTS   AND   APPLIANCES 

edge  of  the  metric  system  of  linear  measurement  and  the  cen- 
tigrade circle,  together  with  their  method  of  adaptation  to  the 
taking  of  the  measurement  of  the  various  parts  of  instruments. 
The  metric  or  French  decimal  system  is  the  one  now 
adopted  by  most  scientific  men  and  the  student  should 
begin  at  once  to  put  its  principles  into  use.  It  is  based  on 
the  French  meter,  which  equals  39.37  inches  in  the 
old  measurement.  The  denominations  of  the  system 
may  be  learned  here,  but  the  only  method  of  thoroughly 
appreciating  them  is  to  put  them  into  actual  practice. 
These  denominations,  so  far  as  their  uses  in  dentistry  require, 
are  as  follows: 

One  Meter 39  inches  (approximate) ' 

One  Decimeter  (one-tenth  of  a  meter) 4  inches  (approximate)" 

One  Centimeter  (one-hundredth  meter) 2/5  inch      (approximate)' 

One  Millimeter  (one-thousandth  meter) 1/25  inch      (approximate). 

Tenths,  hundredths  and  thousandths  of  a  millimeter. 

One  thousandth  of  a  millimeter  is  known  as  a  micron  and  is  used  only  in  microscopic 
work. 

(Table  from  Black's  Operative  Dentistry.) 

The  Centigrade  Circle. — This  is  a  circle  divided  into  one 


270 


180 


Fig.  56. 


-The  centigrade  circle.     25,  50  and  75  centigrades  equal  respectively 
90,  180  and  270  astronomical  degrees. 


hundred  parts  or  degrees,  instead  of  360°,  as  is  the  astronom- 
ical circle.     To  convert  centigrades,  the  degrees  represented 


CENTIGRADE    ANCLES 


ST 


m  this  circle,  into  astronomical  degrees,  multij)ly  ,^6o  ])y  ilic 
number  of  centigradcs  anddivide  by  loo;  or  fa  sim])]er  method) 
after  multiplying,  cut  off  two  fig- 
ures (move  the  decimal  point  two 
figures  to  the  left)  as  in  calculating 
interest  (Fig.  56). 

COMPARISON    OF    CENTIGRADE    AN- 
GLES WITH  ASTRONOMICAL  DE- 
GREES (TABLE  FROM  BLACK) 

6  ccntigrades 21.6  degrees 

12  ccntigrades 43 .  2  degrees 

18  centigrades 64 . 8  degrees 

23  centigrades 82.8  degrees 

28  centigrades 100.8  degrees 

80  centigrades -.288.0  degrees 

95  centigrades 340.0  degrees 


The  Dental  Instrument  Gauge 

The  millimeter  measure  and 
the  centigrade  circle  have  been 
combined  in  an  instrument  known 
as  the  Dental  Instrument  Gauge. 
This  appliance  is  largely  used  by 
instrument  manufacturers  for 
measuring  the  length,  width  and 
angle  of  the  cutting  edge  of  the 
blade  and  the  angles  in  the  shank 
of  the  instrument;  but  its  cost  is 
almost  prohibitive  for  general  use 
of  dental  students.  For  measure- 
ment of  angles  in  the  technic  work, 
m  fact,  for  taking  any  measure- 
ments desired,  good  results  may  be 


57- — Dental    instrument 
gauge. 


52 


INSTRUMENTS   AND   APPLIANCES 


270 


-90 


accomplished  on  the  illustration  here  given  if  the  instrument 
is  not  at  hand  (Fig.  57). 

1.  To  measure  the  width  of  the  blade  lay  it  in  the  small 
slot  numbered  from  o  to  50,  which  will  give  the  width  in 
tenths  of  a  millimeter. 

2.  To  measure  the  length  of  the  blade  lay  it  lengthwise 
in  the  gradations  on  the  principal  bar  and  measure  from  the 

cutting  edge  to  the  first  angle 
in  the  shank,  which  will  give 
the  length  in  millimeters. 

3.  To  measure  the  angle 
of  the  blade  with  its  shaft  lay 
the  handle  or  shaft  on  the 
main  bar  of  the  gauge  and 
parallel  with  the  lengthwise 
lines,  having  the  blade  turned 
toward  the  small  numbers  to 
the  right;  while  holding  it  so, 
bring  the  length  of  the  blade 
parallel  with  one  of  the  gra- 
dations of  the  circle,  which  will  give  the  angle  in  centigrades 
(Fig.  58). 

4.  To  measure  the  angle  of  the  cutting  edge  of  the  blade 
with  its  shaft  lay  the  instrument  in  the  same  position  as 
described  in  3,  and,  without  rotating  it,  move  it  to  the  left 
(keeping  its  shaft  parallel  with  the  lengthwise  lines  on  the 
main  bar  of  the  gauge),  until  the  angle  of  the  blade  is  parallel 
with  one  of  the  gradations  to  the  left  of  the  circular  head. 
This  measurement  is  seldom  necessary,  as  in  most  instruments 
the  cutting  edge  is  at  right  angles  to  the  length  of  the  blade. 
Occasionally,  though,  variations  are  found,  as  in  Black's 
Gingival  Trimmers  and  in  some  varieties  of  chisel. 

5.  To  measure  the  amount  of  bevel  of  a  blade  place 


Fig.  58. — Measuring  the  angle  of  the 
blade  with  its  shaft.  (American  Text- 
book of  Operative  Dentistry.) 


THE  BOLEY   GAUGE 


the  edge  of  the  blade  in  the  center  of  the  circle,  with 
one  side  of  the  blade  on  the  zero  division.  The  figure  ^ 
on  the  periphery  of  the  circle  on  the  line  which  fol- 
lows the  other  side  of  the  blade  will  give  the  amount 
of  bevel  in  centigrades.  The  first  two  measurements 
here  given  are  the  only  ones  in  the  list  of  which  the 
Boley  gauge  is  capable. 

Formula  Names. — Dr.  G.  V.  Black's  set  of  instru- 
ments is  designed  largely  after  the  first  three  methods 
of  measurement  given  above,  and  the  measurements 
are  placed  on  the  shafts  of  the  instruments  in  the 
order  given,  the  first  measurement  representing  the 
width  of  the  blade  in  tenths  of  a  millimeter,  the  sec- 
ond representing  its  length  in  millimeters,  and  the 
third  the  angle  of  the  blade  with  the  shaft.  In  cases, 
however,  where  the  fourth  measurement,  as  described 
above,  is  necessary,  it  is  placed  second  in  the  formula, 
the  entire  set  of  measurements  being  known  as  the 
Formula  Name  of  the  instrument  (Fig.  59). 

The  Boley  Millimeter  Gauge 

This  instrument  is  suflScient  for  measuring  all  but 
the  angles  in  the  blade  and  shank:  of  an  instrument. 
The  smaller  gradations  on  the  gauge  are  millimeters. 
The  instrument  is  capable  of  measuring  as  much  as 
10  millimeters  (i  centimeter)  or  as  little  as  o.i  milli- 
meter (1/250  inch).  For  measuring  in  tenths  of  a 
millimeter  a  small  scale  known  as  the  Vernier,  located 
on  the  sliding  piece  by  which  the  jaws  of  the  instru- 
ment are  opened,  is  used.     On  examination  of  the 


Fig.  59. — Hatchet  excavator  showing  formula  on  the  handle.     Figure;  i 
on  the  end  of  the  handle  is  the  catalogue  number. 


54 


INSTRUMENTS   AND   APPLIANCES 


instrument,  it  will  be  seen  that  the  divisions  of  this  short 

scale  (the  Vernier)  equal  9 
divisions  on  the  main  scale. 
When  the  zero  divisions  on 
the  main  scale  and  the  Ver- 
nier are  together,  the  instru- 
ment is  at  rest  and  is  not 
capable  of  registering  a 
measurement.  Now,  move 
the  first  division  on  the  Ver- 
nier in  contact  with  the  first 
division  on  the  main  scale 
and  the  instrument  will  reg- 
ister 0.1  millimeter;  move 
the  second  divisions  together 
and  0.2  millimeter  are  regis- 
tered; the  third  divisions 
giving  0.3  millimeter,  the 
fourth  divisions  giving  0.4,^ 
the  fifth  divisions  giving  0.5, 
and  thus  continuing  until  i 
millimeter  is  registered.  The 
Boley  gauge  is  valuable 
for  measuring  instrument 
blades,  plugger  points,  drills, 
burs,  differences  in  the  meas- 
urement of  teeth  of  the  same 
denomination  in  the  mouth, 
in  comparing  measurements, 
in  restoring  angles  of  teeth 

Fig.  60. — Boley  millimeter  gauge.  .  ,  ,  ,     .,  i . 

m  gold-buildmg  operations, 
in  selecting  artificial  teeth,  and  many  other  cases  arising  in 


INSTRUMENT   NOMENCLATURE  55 

dental  practice.  It  should  be  in  the  hands  of  every  dental 
student  and  practitioner  (Fig.  60). 

Instruments  are  known  as  Long-handle  Instruments  if 
the  handle,  shank  and  blade  are  all  made  from  one  piece  of 
steel;  if  the  shank  and  blade  or  nib  are  separate  from  the 
handle  and  intended  to  be  screwed  into  it,  the  instrument 
is  known  as  a  Cone-socket  Instrument.  Examples  of  long 
handle  instruments  are  shown  in  Fig.  71,  while  the  Black  set 
of  pluggers  seen  in  Fig.  86  are  of  the  cone-socket  \'ariety. 
The  advantage  in  the  cone-socket  instrument  is  that,  if  the 
working  part  is  broken,  it  may  be  replaced  at  less  expense;  the 
disadvantage  is  its  tendency  to  loosen  at  the  joint.  Students 
should  see  that  all  cone-socket  instruments  are  screwed  tight  into 
the  handles  before  using. 

Bevels. — The  blades  of  some  cutting  instruments,  such 
as  chisels,  are  beveled  on  only  one  side,  while  others,  such  as 
Hatchet  Excavators,  are  bi-beveled,  that  is,  beveled  on  both 
sides  (see  Figs.  61  and  62). 

Rights  and  Lefts. — Instruments  are  frequently  made  in 
pairs,  the  angles  in  the  shank  throwing  the  working  point  of 
one  to  the  right  and  of  the  other  to  the  left,  both  instruments 
being  intended  to  do  the  same  character  of  work  on  opposite 
sides  of  a  ca\'ity  or  the  mouth.  These  are  known  as  Rights  and 
Lefts.  Familiar  examples  are  spoon  excavators  and  various 
hand-pluggers.    See  Fig.  61 — Spoons  10,  6,  12  L;  10,  6,  12  R. 

Names  of  Instnmients. — The  names  of  instruments  are 
classified  as  follows: 

1.  Order  Names. — These  names  denote  the  purpose  for 
which  the  instrument  is  intended,  as  excavator,  plugger, 
chisel,  drill,  mallet. 

2.  Sub-order  Names. — These  define  the  manner  or  posi- 
tion of  use  of  the  instrument;  as  automatic  mallet,  hand 
plugger,  pull  scaler,  bicuspid  clamp. 


56  INSTRUMENTS   AND   APPLIANCES 

3.  Class  Names  describe  the  working  point  of  the  instru- 
ment; as  hatchet  excavator,  spoon  excavator,  round  bur, 
inverted  cone  bur,  serrated  plugger. 

4.  Sub-class  Names  indicate  the  shape  of  the  shank;  as 
Mon-angle,  Bin-angle,  Triple-angle,  Contra-angle. 

These  names  are  frequently  combined  in  the  description 
of  instruments,  as  Mon-angle  Hatchet  Excavator,  Gingival 
Margin  Trimmer,  Triple- angle  Contra-angle  Spoon  Excavator. 

CLASSIFICATION  OF  INSTRUMENTS 

For  purposes  of  description,  instruments  may  be  divided 
into  (i)  Cutting  Instruments,  (2)  Condensing  Instruments, 
(3)  Miscellaneous  Instruments.  A  brief  description  of  each 
class  follows : 

I .  Cutting  Instruments.^ — Definition :  Instruments  for  the 
cutting  of  the  hard  and  soft  tissues  of  the  mouth,  removal  of 
deposits  from  the  teeth,  and  for  finishing  fillings. 

(a)  Excavator  (h)  File 

(b)  Chisel  (i)  Saw 

(c)  Bur  (j)  Knife 

(d)  DriU  (k)  Wheel 

(e)  Reamer  (1)  Point 

(f)  Lancet  (m)  Disk 

(g)  Scaler  (n)  Strip 

(a)  Excavator. — An  instrument  for  the  excavation  and 
removal  of  decay  and  the  shaping  of  the  internal  parts  of 
cavities.  There  are  five  forms,  viz.,  the  hatchet,  the  hoe,  the 
spoon,  the  discoid  and  the  cleoid.  Their  names  indicate  their 
form,  they  being  designed  after  the  ordinary  hatchet,  hoe, 
spoon,  etc.  (Fig.  61). 

The  hatchet  excavator  (Fig.  61;  12-5-12)  has  the  edge  of 
the  blade  running  in  a  direction  parallel  with  the  handle,  and 


EXCAVATORS   AND   CHISELS 


57 


is  bi-bevelcd.  In  the  hoe  excavator  (Fig.  6i;  8-3-23)  the  edge 
of  the  blade  is  beveled  on  the  side  distal  (away  from)  to  the 
shaft  and  runs  at  right  angles  to  it.  The  hatchet  and  hoe  are 
used  for  the  removal  of  the  harder  varieties  of  decay  and  to 
give  form  to  the  internal  parts  of  cavities.  The  spoons  (Fig. 
Oi;  10-6-12)  and  discoids  (round  spoons)  are  intended  es- 
pecially for  the  scooping  out  of  soft  decay,  and  are  beveled 
only  on  the  distal  (far)  side.  Clcoid  means  claw-like,  the 
instrument  having  a  sharp  point,  with  two  rounded  edges 
running  from  it — really  a  spoon  excavator  with  the  blade 


12 

12 

B 

12 

12 

5 

5 

3 

S 

5 

IZ 

23 

23 

6 

12 

15 

10 

10 

15 

15 

10 

8 

S 

s 

95 

95 

6 

12 

12 

12 

8 

8 

6 

R 

U 

R 

12 
L 

12 

Fig.  61. — Black  cutting  instruments.  Hatchet,  hoe  and  spoon  excavators, 
enamel  hatchets,  gingival  margin  trimmers  and  a  bin-angle  chisel.  Formula  names 
are  shown. 

running  to  a  sharp  point.     It  is  especially  designed  for  deepen- 
ing the  angles  of  pulp  chambers  at  the  canal  entrances. 

(b)  Chisel. — An  instrument  designed  after  the  ordinary 
carpenter's  tool,  and  intended  for  cutting  enamel.  It  is 
beveled  on  only  one  side,  and  the  shank  may  be  straight  or 
bin-angled  (Fig  62).  Enamel  Jiatchet  is  a  variety  of  chisel 
in  which  the  blade  (bcvelled\)n  one  side)  is  placed  in  hatchet 
form  by  contra-angling  the  shank  (Fig.  61;  15-8-12).  It  is 
made  in  rights  and  lefts  with  the  bevel  on  opposite  sides  for 
cutting  enamel. 


58 


INSTRUMENTS    AND    APPLIANCES 


Gingival  Margin  Trimmer. — A  variety  of  chisel  especially 
designed  for  giving  the  proper  bevel  to  gingival  enamel  mar- 


FiG.  62. — Chisels. 


Fig.  63. — Engine  burs  (enlarged).    The  cone  bur,  being  almost  obsolete'is  not 

shown. 


gins;  made  in  rights  and  lefts,  two  pairs  of  different  size  for 


ENGINE  BURS 


59 


beveling  mesial  ca\ities  (ca\'ities  on  the  mesial  surface)  and 
two  pairs  for  distal  ca\ities  (Fig.  6r;  15-Q5-S-12). 

(c)  Bur. — A  form  of  drill  for  revo- 
lution in  the  handpiece  of  the  dental 
engine,  intended  for  the  rapid  cutting  of 
tooth  structure  during  the  removal  of  de- 
cay and  preparation  of  cav'ities.  Burs 
may  be  di\-ided  into  two  groups,  according 
to  shape  and  depending  on  whether  in- 
tended to  cut  round  or  plane  surfaces 
(Fig.  63). 


Fig.  64. 


The  round 
bur.  Showing  formation 
of  the  cutting  blades. 


Fig.  65. — Enlarged  dentate  burs. 


I 


f  i\ 


I 


1 


Fig.  66. — Spear-point  drills. 


1  ; 


Fig.  67. — Square  drills. 


6o 


INSTRUMENTS   AND   APPLIANCES 


Group  I  for  cutting  concave  surfaces,  includes  the  round 
(Fig.  64),  oval,  pear,  bud  and  pointed  fissure  burs. 

Group  2  for  cutting  plane  surfaces  and  angles,  includes 
the  cone,  inverted  cone,  wheel  and  square  or  Hat-end  fissure  burs. 

Dentate  Burs  are  burs  with  the  cutting  blade  divided  into 
teeth,  very  rapid  cutters,  intended  especially  for  attacking 
enamel  (Fig.  65). 

Plug-finishing  Burs  are   burs  of  a  finer   cut,  of   similar 
shape  to  those  mentioned  in  Groups  i 
and  2,  intended  tor  finishing  and  bur- 
nishing fillings. 

(d)  Drill. — An  engine  instrument 
used  for  boring  or  drilling  holes  in 
tooth  structure  (as  in  opening  into  a 
pulp  chamber  from  the  surface,  where 


Fig.  68.— Twist  drills. 


Fig.  69. — Gates -Glidden  reamers. 


no  cavity  exists)  or  in  bone  (as  during  the  treatment  of  an 
alveolar  abscess).  A  drill  is  also  valuable  for  following  out 
fissures  and  for  removal  of  old  fillings.  The  Spear-point 
(Fig.  66),  Square  (Fig.  67)  and  Twist  (Fig.  68)  drills  are 
familiar  forms.  A  special  form,  known  as  a  Diamond  drill, 
is  valuable  for  drilling  cavities  in  artificial  teeth.  Drills  may 
be  readily  made  from  old  fissure  and  inverted  cone  burs  by 
beveling  them  on  opposite  sides.  A  bi-beveled  dentate  fissure 
bur  made  from  an  old  dentate  bur  is  valuable  for  drilling 
through  enamel  and  dentin. 


REAMERS — LANCETS 


6i 


(e)  Reamer. — An  engine  instrument  for 
enlarging  root  canals  during  treatment. 
Drills  should  never  be  used  for  this  pur- 
pose on  account  of  the  danger  of  perfora- 
tion. A  flexible  reamer,  which  will  follow 
the  route  of  the  canal  and  enlarge  it,  is  usu- 
ally indicated.  Well-known  varieties  are 
the  Beutclrock  and  Gates-Glidden  reamers 
(Fig.  69).  The  Peeso  and  Ottolengui  root 
reamers  (non-flexible)  are  used  for  great  en- 
largement during  the  placing  of  dowels. 
The  Kerr  tapered  canal  reamers  (spiral  form) 
(Fig.  70)  are  valuable  for  enlarging  the  en- 
trance to  canals. 

(f)  Lancet. — Synonyms,  Scalpel,  Bis- 
toury. An  instrument  of  knife  form,  de- 
signed for  cutting  the  soft  tissues.  Lancet 
is  applied  more  frequently  to  that  form  of 
knife   for   use  about  the  mouth,  as  in  the 


BCD  22  7 

Fig.  70. — Kerr  tapered  canal  reamers. 
B,  C,  and  D  arc  hand  instruments.  2,  2 
and  7  are  for  the  engine. 


Fig.    71. —  Bis- 
touries. 


62 


INSTRUMENTS    AND    APPLIANCES 


lancing  of  abscesses  and  in  all  minor  oral  surgery  operations 
(Fig.  71). 

(g)  Scaler. — An  instrument  for  the  removal  of  calculus. 
The  blade  is  similar  to  the  hoe  and  hatchet  excavator.     The 

instrument  has  various  angles 
in  the  shank,  and  is  used  mostly 
with  a  pull  cut  (Fig.  72). 
Scalers  are  made  in  rights  and 
lefts,  in  many  different  sizes  and 
shapes,  some  for  the  removal 
of  large  deposits  on  the  crowns 
of  teeth,  and  others  for  minute 
particles  at  the  neck  and  under 
the  gum  (Fig.  73). 

(h)  File. — An  instrument  designed  for  filing  down  or  re- 
moving surplus  filling  material.  The  Black  (Fig.  74),  Searle 
and  ''Flexo^'  files  (Fig.  75)  are  prominent  examples.     Rheine's 


Fig.  72. — S.  S.  White  scalers. 


Fig.  73. — Thompkin's  scalers. 

and  D.  D.  Smith's  Approximal  Trimmers,  popular  varieties, 
are  also  useful. 

(i)  Saw. — The  saw  is  generally  used  in  a  special  frame, 
and  has  teeth  on  one  or  both  sides.     It  is  useful  for  separating 


I'lT.F.S,    SAWS    ,\\n    KNWES 


63 


Icclh  and  for  trimmin<^f  siir])lus  material  from  jjroximal  fillings. 
The  Kacbcr,  Wilson,  Clapp,  Ciordoii-Whilc  and  '''thin-ribbon^^ 


Fig.  74. — Black  files. 

saws  are  prominent  varieties  (Fig.  76). 

(j)  KJnife. — Synonym,  Trimmer.  An  in- 
strument with  a  thin,  knife-hke  blade,  made 
in  various  shapes,  designed  for  trimming  or 
shaving  off  surplus  filling  material  at  the  gingi- 
val, buccal  and  lingual  margins  of  proximal 
fillings.  Black^s  (Fig.  77),  Wedelstaedfs,  Pich- 
Icr's  (Fig.  78)  and  Gordon-Whitens  are  all  use- 
ful examples. 

(k),  (1),  (m),  (n)  Wheel,  Point,  Disk,  Strip. 
— ^Wheel.  A  small  grindstone,  ranging  from 
1/2  inch  to  I  inch  in  diameter,  of  various  thick- 
nesses and  made  of  corundum  or  carborundum, 
of  which  the  latter  is  harder,  cuts  more  rap- 
idly and  lasts  longer  (Fig.  79).  Point,  Disk. 
Made  of  the  same  materials  and  of  vulcarbo, 
the  Point  (Fig.  80)  being  of  various  shapes,  as 
barrel,  cone,  bud,  bell,  etc.,  and  ranging  in 
several  sizes.  Also  made  of  Arkansas,  Scotch 
and  Hindoostan  stone  when  intended  for  finer 
grinding,    these   materials  being   of    a    much 


64 


INSTRUMENTS    AND   APPLIANCES 


\. 


Fig.  75.— "Flexo"  file. 


Fig. 76.— 
frame 


-Kaeber  saw- 
and  saw. 


smoother  grain  than  carborundum.  The 
"Gem''  Point  is  excellent  for  finer  grinding 
and  for  cavity  margins.  The  Diamond  Point 
and  Disk  are  likewise  valuable  for  cutting 
enamel,  separating  and  finishing.  The  Dia- 
mond is  largely  utilized  in  this  form  for 
drilling  cavities  in  artificial  teeth.  Disks 
(Fig.  St,)  are  also  made  of  paper  and  cloth, 
charged  with  emery,  sand,  garnet  and  cut- 
tle-fish bone  for  polishing  purposes  (Fig. 
82).  The  cuttle-fish  disk  is  the  finest  grain 
of  these,  and  is  intended  for  very  fine  cut- 
ting and  polishing.  A  variety  of  disk  known 
as  Crocus  is  very  valuable  for  putting  an  ex- 
tremely velvety  finish  to  gold  fillings. 
Disks  for  carrying  polishing  powders,  such  as 
pumice,  corundum  flour,  chalk,  oxide  of  tin, 
whiting  and  rouge  are  made  of  celluloid, 
felt,  leather,  moose  hide,  soft  rubber,  cham- 
ois, etc. ;  while  points  for  the  same  purpose 
are  made  of  wood,  leather,  felt,  chamois  and 
soft  rubber  (Fig.  81).  Special  mandrels 
are  made  for  mounting  all  of  the  above 
(Fig.  84).  Cloth  and  paper  STRIPS  of 
various  widths  and  charged  with  the  same 
materials  as  the  disks,  as  well  as  with  car- 
borundum, flint  and  lava,  are  utilized  for 


KNIVES,    WHEELS   AND   POINTS 


6s 


-^ 


Fig.  77. — Black  knives. 


n 


Fig.  78. — Pichler  knives 
Right  and  left. 


Fig.  79. — Carborundum  wheels. 


6 


Fig.  80. — Carborundum  points. 


66 


INSTRUMENTS   AND   APPLIANCES 


Fig.  8i. — Soft  rubber  polishing  points. 


t^      Fig.  82. — Emery  cloth  disks. 


Fig. 


-Disk 


mandrel. 


-Carborundum  disks. 

finishing  and  polishing  fillings.  Celluloid  strips 
are  valuable  for  finishing  silicate  fillings  and  for 
use  as  matrices. 

Sharpening  Cutting  Instruments. 

The  workman  is  known  by  his  tools.  A 
glance  into  the  operating  case  of  a  student  or  a 
dentist  is  sufficient  to  enable  a  good  judge  to 
gauge  the  capabilities  and  character  of  work 
being  done  by  its  owner. 

Cutting  instruments  should  he  kept  sharpened 
if  ideal  results  are  desired.  The  possession  of 
a  good  Arkansas  stone  (Fig.  85)  is  essential  to 
the  attainment  of  this  object.     The  stone  should 


SHARPENING   INSTRUMENTS 


67 


be  slightly  moistened  with  a  droi)  or  two  of  lubricating  oil. 
Avoid  too  much  oil.  The  passage  of  an  excavator  or  chisel 
over  the  stone  with  a  few  long,  firm  strokes  will  be  suffi- 
cient, if  resorted  to  at  regular  intervals,  to  keep  the  instru- 
ment sharp.  Care  should  be  taken  to  follow  the  original 
bevel  of  the  blade  and  not  to  establish  false  bevels  during 
the  sharpening  process. 


wmmF^. 


FOR     SALE     BY 

THE    S.S.WHITE 

DENTAL  MFG.   CO. 


(^^ 


Fig.  85. — Arkansas  stone  in  case. 


The  stone  should  rest  on  a  firm  surface,  should  be  kept 
clean  and  free  from  grit  and  scratches.  Some  dentists  prefer 
to  hold  the  instrument  to  be  sharpened  in  the  left  hand 
while  manipulating  the  stone  backward  and  forward  wdth 
the  right. 

2.  Condensing  Instruments. — Definition:  Instruments 
designed  for  packing,  plugging  or  condensing,  mixing  and 
smoothing  filling  materials. 


68 


INSTRUMENTS   AND   APPLIANCES 


(a)  Plugger 

(b)  Burnisher 

(a)  Plugger. — An    instrument    designed    for    plugging, 


(c)  Spatula 

(d)  Mallet. 


10 

5 

5 

7\ 

10 

5 

6 

12 

5 

20 

15 

15 

5 

7l 

5 

10 

12 

6 

5 

5 

5 

3 

3 

10 

10 

10 

1 

6 

6 

1 

2 

5 

3 

2 

3 

3 

3 

3 

3 

3 

0 

10 

10 

23 

18 

12 

18 

23 

0 

1        2        3        4        5      B  7        8        9       10       11       12       13      14 

Fig.  86. — G.  V.  Black  set  of  cone-socket  plugger  points.     Formula  names  are 

given, 

packing  or  condensing  filling  materials,     (i)   Gold  and  (2) 
Amalgam  Pluggers.     (i)  Gold  Plugger  (Fig  86) .     For  plugging 


•  isa  "  CSS     ■  sa       - 


na      -  SB   O 


9  10  II         12        13 


Fig.  87. — Varney  set  of  gold  pluggers — cone-socket. 

or  building  gold,  a  plugger  with  a  small  face  or  nih  should  be 
used  (0.5  mm.  to  i  mm.  in  size) ,  while  for  the  final  condensa- 


GOLD   PLUGGERS 


69 


lion  of  the  filling  a  larger  size  (foot  plug- 
ger)  should  be  utilized.  The  gold  plug- 
ger  is  made  for  hand  pressure,  hand- 
mallet  or  some  form  of  mechanical  mal- 
let (Fig.  87) .  The  working  point  or  nib 
is  serrated  (Fig.  88)  and  in  most  in- 
stances presents  a  plane  surface,  though 
some  are  rounded  or  convex,  while  some 
are  concave  (Fig.  89).  The  outHne 
form  is  either  round,  oval,  square,  ob- 
long or  parallelogram,  triangular,  or 
foot-shaped  (Fig.  90).  (2)  Amalgam 
Plugger.  For  packing  and  condensing 
amalgam  a  larger  size  plugger  is  indi- 
cated, the  selection  depending  on  the 
size  and  shape  of  the  cavity  (Fig.  91). 
The  amalgam  plugger  should  be  ser- 
rated to  obtain  the  best  results,  though 
many  with  smooth  faces  (burnishers) 
are  manufactured.  Amalgam  pluggers, 
as  well  as  gold  pluggers,  are  made  in 
cone  socket  or  long  handle,  with  all 
forms  of  angle  in  the  shank  (Fig.  92). 

(b)  Burnisher. — An  instrument  de- 
signed for  burnishing  and  smoothing  the 
surface  of  a  filling  and  for  inserting 
cement,  gutta-percha  and  amalgam  into 
cavities  (Figs.  93,  94  and  95).  Bur- 
nishers are  made  of  steel,  agate,  blood- 
stone, ivory,  German  silver  and  tan- 
talum. For  burnishing  the  surfaces  of 
fillings,  steel  is  the  best  material,  while 
for  working  cements,  instruments  made 


CD 


Fig.  88. — Diagrammatic 
illustration  showing  serra- 
tions in  the  nibs  of  the  round 
instruments  in  the  Black 
set  of  pluggers. 


70 


INSTRUMENTS   AND   APPLIANCES 


N/1 


j^/^ 


Fig.  89. — Serrated  nibs,  parallelogram  form.     Black  pluggers. 

of  some  of  the  other  materials  may 
be  utilized.  The  silicate  cements  do 
not  allow  of  contact  with  steel,  so  that 
the  agate,  tantalum,  ivory  and  tortoise- 
shell  instruments  are  used  in  their 
manipulation.  Burnishers  are  pri- 
marily hand  instruments,  but  they  are 
also  made  to  be  used  in  the  engine  hand 
piece  for  burnishing  the  surface  of  fil- 
lings, when  they  are  known  as  engine 
burnishers. 

(c)  Spatula. — An  instrument  with 
a  flat,  unsharpened  blade,  made  in  vari- 
ous sizes,  for  mixing  cement  and  for 
introducing  and  smoothing  the  surface 
of  cement  fillings.  A  spatula  is  made 
of  steel,  German  silver,  bone,  tantalum 
or  other  material  (Fig.  96). 

(d)  Mallet. — Hand  and  Mechanical. 
The  hand  mallet  is  made  of  wood,  lead, 
steel  and  other  materials,  in  various 
sizes  and  weights.  It  is  utilized  for 
malleting  gold  and  amalgam  fillings, 
driving  wedges  in  separating  teeth  and 


Fig.  90. —  Foot    pluggers 
Black  set. 


VARIETIES   OF   MECHANICAL  MALLETS 


yr 


in  delivering  blows  for  other  purposes,  as  in  chiselling  enamel. 
The  mechanical  mallet,  designed  for  plugging  gold,  is  of  four 


25 

35 

10 

30 

15 

35 

30 

10 

35 

15 

7 

7 

7 

7 

7 

7 

12 

12 

12 

12 

12 

12 

2 

3 

4 

5 

6 

7 

Fig.  qi. — G.  V.  Black  set  of  amalgam  pluggers. 


varieties,  \dz. : 

(i)  The  Automatic  (the  most  popular), 
in  which  the  blow  is  dehvered  to  the  plugger 
by  the  releasing  of  an  actuating  spring  con- 
cealed in  its  shaft  (Fig.  97) : 

(2)  The  Engine  or  Mechanical  (used  on 
the  dental  engine),  its  action  depending  on 
the  rapid  revolution  of  a  disk  with  a  projec- 
tion in  its  rim: 

(3)  The  Pnewuatic  (now  almost  obso- 
lete), which  is  worked  by  the  forcible  pres- 
sure of  air  from  a  bulb  onto  its  piston;  and 

(4)  The  Electric  (the  most  rapid  and 
valuable),  which  is  propelled  by  the  electric 
current. 

3.  Miscellaneous  Instruments. — Instru- 
ments of  miscellaneous  character  not  classi- 
fied under  either  of  the  previous  headings: 


72 


INSTRUMENTS   AND   APPLIANCES 


t  J 


Fig.  92. — ^Loaded  amalgam 
carrier  and  plugger. 


Fig  .^93. — Burnisher. 


MISCELLANEOUS   INSTRUMENTS 


73 


(a)  Explorer 

(b)  Broach 

(c)  Separator 

(d)  Matrix 

(e)  Pliers 


(f)  Clamp 

(g)  Scissors 
(h)  Syringe 
(i)    Mandrel 


(a)  Explorer. — Cavity  Explorer — Canal  Explorer.  A  cav- 
ity explorer  is  a  small,  sharp-pointed  instrument,  made  in 
various  shapes  for  searching  out  cavities  of  decay  (Fig.  98). 
A  ca7tal  explorer,  or  smooth  broach,  is  a  small,  delicate  instru- 


FiG.  94.— Burnisher.  Fig.  95. — Thin  burnishers. 

ment,  with  a  long  taper  and  sharp  point,  made  in  various 
sizes  for  following  the  intricacies  of  canals. 

(b)  Broach. — An  instrument  designed  for  the  exploration, 
measurement  of  the  length  and  dimension,  removal  of  the 
contents,  enlargement  and  filling  of  root  canals. 

(i)  Smooth  broach 

(2)  Hooked  broach 

(3)  Barbed  broach 

(4)  Twist  broach 

(i)  A  smooth  broach,  in  addition  to  the  uses  already  given, 
is  also  utilized  for  placing  dressings  in  and  drying  out  canals. 


74 


INSTRUMENTS   AND   APPLIANCES 


m 


Fig.  96. — German 
silver  cement  spatu- 
las. The  metal  is 
not  acted  upon  by 
the  cement  liquid. 


lEiDENTA 

'Win 


Fig.  97. — Auto- 
matic plugger. 


lU. 


L 


I        2  3 

Fig.  98. — Double  end  cavity  ex- 
plorers. Rights  and  lefts.  Num- 
bers 2  and  3  are  contra-angles. 


FORMS  AND  USES  OF  BROACHES 


75 


One  variety  is  round,  another  is  square  (also  known  as  a  Swiss 
or  Jeweler's  broach  or  reamer)  and  others  are  three  or  five 
sided.  The  smooth  broach  may  be  obtained  annealed  or 
un-annealed,  the  im-annealed  variety  being  extremely  brittle 


Fig.  99. — Enlarged  barbed  broach. 


Fig.  100. — S.  S.  White  canal  cleaners.     (Barbed  broaches.)     I 


^ 


I        A      B         C       D         6         78 

Fig.  ioi. — Kerr  twist  or  spiral  broaches.     No.  i  is  enlarged.     B  is  a  nub-broach. 

Nos.  6,  7,  8,  are  for  the  engine  hand-piece. 


Fig.  102. — ]\Ictal  broach-holder. 


and  easily  broken.  For  canal  work  the  temper  should  usually 
be  drawn,  as  already  described.  (2)  Hooked  hroaeh — hooked 
extractor — a  smooth  broach  with  a  hook  on  the  end,  either 
at  a  right  or  acute  angle,  used  for  removing  pulps  and  for 


76 


INSTRUMENTS    AND    APPLIANCES 


measuring  the  length  of  canals.  (3)  Barbed  broach — canal 
cleanser — a  broach  with  small  barbs  or  teeth,  used  for  remov- 
ing pulps  and  for  rasping  the  sides  of  canals  during  cleansing 
and  enlarging  operations  (Fig.  99).  It  is  made  in  extra 
fine,  fine,  medium,  or  large  sizes  and  may  be  obtained  in 
packages  of  six  assorted,  or  in  the  separate  sizes.  Prominent 
forms  are  the  Donaldson,  the  S.  S.  White  (Fig.  100)  and  the 
Fellowship  broaches.  (4)  Twist  broach.  A  tapered  spiral 
broach,  designed  and  operated  on  the  principle  of  an  auger, 


Fig.    103. — Ivory   universal 
double-bow  separator. " 


Fig.  104. — Ivory  separator.     New  form. 


for  enlarging  or  reaming  canals  (Fig.  loi).  It  is  made  in 
extra  fine,  fine,  medium,  coarse  and  extra  coarse  sizes,  and  is 
a  much  safer  instrument  than  the  engine  reamer.  It,  as 
well  as  the  other  varieties  of  broach,  is  designed  to  be  used 
either  in  a  broach  handle  (broach  holder)  (Fig.  102)  or  as  a  long- 
handle  instrument.  There  is  also  a  variety  of  twist  broach 
known  as  a  Nub  broach  (see  illustration.  Fig.  loi)  intended  for 
operations  on  the  lower  teeth.  Of  these  the  Downie  and 
Kerr  are  the  most  prominent  makes. 


SEPARATORS   AND   MATRICES 


77 


(c)  Separator. — A  steel  instrument,  designed  for  forcing 
apart  (wedge  separator)  or  drawing  apart  (traction  separator) 
two  approximating  teeth,  thus  gaining  space  for  making 
examination  of,  or  operating  in,  inter-proximal  spaces.  The 
wedge  separator  acts  on  the  principle  of  a  wedge,  by  the  forcing 
together  of  two  steel  points;  the /rac/^'f?w  separator  Sicts  in  the  op- 
posite manner  by  the  drawing  apart  of  two  pairs  of  points; 
while  some  instruments  combine  both  principles.  The  Ivory 
(Figs.  103  and  104),  ^'Perry^'  (Fig.  105),  '^Little  Giant''  and 
Elliot  (Fig.  106)  separators  are  prominent  examples. 


Fig.  105. — Perry  separators. 


Fig.  106. — Elliot  separator. 


Separation  of  the  teeth  is  also  accomphshed  through  the 
expansive  properties  of  such  materials  as  wood,  cotton, 
linen  tape  and  gutta-percha  (slow  or  previous  separation). 

(d)  Matrix. — A  thin  band  or  strip  of  steel,  German  silver 
or  copper  about  o.ooi  inch  in  thickness,  used  to  restore  the 
fourth  or  missing  wall  in  filling  proximo-occlusal  cavities, 
thus  converting  them  into  simple  cavities.  The  simplest 
form  of  matrix  is  a  thin  strip  of  metal  held  in  position  by  means 
of  a  wooden  wedge.  The  patent  varieties  of  matrix  are  nu- 
merous, consisting  of  the  matrix  band  and  its  retainer,  and 


78 


INSTRUMENTS   AND   APPLIANCES 


range  from  those  occupying  one  inter-proximal  space  to  those 
partially  or  completely  encircling  one  or  two  teeth.  In  some, 
provision  is  made  for  immediate  separation  of  the  teeth 


Fig.  107. — Ivory  matrix  retainer  No.  i  and  matrix  bands. 


Fig.  108. — Ivory  matrix  retainer  No.  8  with  bands. 

during  their_ application.     The  Ivory,  Brophy,  Woodward  and 
Crenshaw  are  prominent  forms  (Figs.  107  and  108). 

(e)  Pliers. — "A  kind  of  pinchers  by  which  any  small 
object  may  be   seized   and  bent" — Webster's   Unabridged 


PLIERS   AND   CLAMPS 


79 


Dictionary.  Dressing  Pliers  are  utilized  for  carrying  cotton 
for  purposes  of  swabbing,  drying 
or  medicating  cavities  and  pulp 
chambers.  Another  variety  of 
pliers,  known,  as  a,  foil  carrier,  is 
used  for  handling  gold,  the  beaks 
of  some  of  these  being  serrated, 
when  they  are  known  as  plugging 
pliers.  Cone-socket  pliers  are  used 
for  tightening  cone-socket  instru- 
ments in  the  handle. 

(f)  Clamp. — "Something  that 
fastens  or  binds" — Webster's.  A 
rubber  dam  clamp  is  a  small  steel 
appliance  to  clamp  the  neck  of  the 
tooth  and  hold  the  rubber  dam  in 
position  (Figs.  109  and  no).  An 
infinite  variety  of  forms  and  sizes 
have  been  designed  for  every  con- 
ceivable shape  of  tooth,  although 
the  bicuspid  and  molar  clamps  are 
most  used.  They  are  carried  into 
position  by  means  of  rubber  dam 
clamp  forceps  (Fig.  in).  The 
''Ivory"  and  "S.  S.  White"  line  of 
clamps  are  the  most  prominent 
varieties.  A  form  known  as  the 
cervical  clamp  is  utilized  in  cases 
where  it  is  necessary  to  force  the 
dam  well  up  beyond  the  margin  of 
cervical    cavities.     Of    these    the 

Fig.  109. — S.  S.  \\  mtc  rubber 
Ivory  (Fig.  112),  Dunn,  Johnson,  dam  clamps  for  molars.  The  ivory 
/T^.  \    T^     r         J  j-T        /-T"  \     clamps  are  practicalK^  of  the  same 

{l\g.ii^),Keefed.ndHow{Y\g.ii^)    form! 


8o  INSTRUMENTS   AND   APPLIANCES 

may  be  mentioned.  Matrix  Clamp  is  another  name  for 
Matrix  Retainer.  A  Cotton  Roll  Clamp  is  a  clamp  designed 
to  hold  napkins  or  cotton  rolls  in  position  in  the  mouth  for 
excluding  moisture. 

Adjuncts  and  Accessories 

(a)  Ligature 

(b)  Rubber  Dam 

(c)  Absorbent 

(d)  Mirror 

(e)  Scissors 

(f)  Syringe 

(a)  Ligature. — Waxed  floss  silk  is  the  most  popular  ma- 
terial for  ligating  the  rubber  dam  in  position.     Hemp  thread 


Fig.  no. — Rubber  dam  clamps  for  anterior  teeth. 

or  gilling  twine  and  small  sea-grass  fish  line  are  also  used  for 
this  purpose,  as  well  as  for  regulating  teeth,  on  account  of 
their  additional  strength.  Brass  and  copper  wire  are  like- 
wise valuable  for  this  purpose  in  special  cases. 

(b)  Rubber  Dam  (c)  Absorbent. — In  operating  in  the 
mouth,  dryness  is  essential.  For  short  operations,  the  teeth 
to  be  operated  upon  may  be  excluded  from  moisture  by  the 
use  of  small  folded  napkins,  or  cotton  rolls  (absorbents)  of 
various  sizes.  For  long  operations  small  holes  are  punched 
in  rubber  cloth  (rubber  dam)  and  this  is  ligated  in  position, 
or    held,  by  means   of   rubber  dam  clamps  (Figs.   115  and 


ADJUNCTS   AND   ACCESSORIES 


Fig.  III. — Rubber  dam  clamp  forceps. 


82  INSTRUMENTS   AND   APPLIANCES 

II 6).     For  drying  the  surfaces  of  teeth,  cavities,  pulp  cham- 


m 

'"luiiimiiiiJiiiii* 

Fig.  112. — Ivory  cervical  clamp.      Fig.  113. — Johnson  cervicardamp. 


Fig.  115. — Adjusting  the  rubber  dam.        Fig.  116. — The  rubber  dam  adjusted. 

bers  and  canals,  cotton,  cottonoid,  spunk  and  bibulous  paper 
(absorbents)  are  the  principal  agents  used. 


ADJUNCTS   AND   ACCESSORIES 


83 


X 


Fig.  117.— 
Mouth  mir- 
ror with  con- 
tra-angled 
shank. 


Fig.    iiS. — Water  syringe  with 
rul)ber  bulb. 


Fig.  119. — Chip  blower. 


84 


INSTRUMENTS   AND   APPLIANCES 


(d)  Mirror. — For  reflecting  the  light  into  various  parts 

of  the  mouth  and  for  reflecting 
the  images  of  cavities,  fillings 
and  other  objects  in  inacces- 
sible positions,  the  mouth 
mirror,  either  plane  or  magni- 
fying is  utilized  (Fig.  117). 
For  general  work,  the  plane 
mirror  (non-magnifying)  is 
best,  while  for  examining  pur- 
poses the  concave  (magnifying) 
mirror  may  be  used. 

Various  forms  of  scissors 
for  cutting  superfluous  gum 


Fig.  1 20.— Ainsworth  rubber  dam  punch.  Fig.  i  2 1  .—Alcohol  lamp,  flame  shield 

and  gold  annealer. 


ADJUNCTS    AND    ACCESSORIES 


8S 


Fig.  122. — Re- 
volving head  engine 
bur  holder  for  labo- 
ratory use. 


Fig.  123. — Dental  engine. 


86  INSTRUMENTS   AND   APPLIANCES 

tissue,  cotton,  gold  and  rubber;  water  syringes  (Fig.  ii8): 
hot  air  syringes  and  chip  blowers  (Fig.  119)  for  drying  and 
removing  debris  from  cavities  and  canals;  rubber  dam  punches 
(Fig.  120)  for  punching  holes  in  the  rubber  cloth;  as  well  as 
many  other  accessories  and  appliances,  will  gradually  become 
familiar  articles  to  the  student,  and  will  not  be  touched  upon 
here  (Figs.  121,  122  and  123). 

INSTRUMENT  MAKING 

Object. — To  gain  a  knowledge  of  the  process  of  hardening, 
tempering  and  annealing  steel;  of  the  proper  methods  of 
shaping  and  sharpening  tools;  of  the  reason  for  placing  the 
various  angles  in  the  shanks;  as  well  as  gaining  a  familiarity 
with  the  class,  subclass,  order  and  formula  names  of  the 
instruments. 

Instrument  blanks  (see  Fig.  228)  may  be  obtained  from 
the  various  dental  instrument  manufacturers — either  in  long- 
handle  or  cone-socket  forms.  The  blanks  are  annealed,  but 
should  be  re-annealed  by  the  student  before  beginning  the 
technic  exercises  in  instrument  making.  The  amount  of 
technic  work  to  be  done  will  be  regulated  by  the  time  at  the 
disposal  of  the  class.  Where  time  will  not  permit  of  the 
making  of  a  set  of  cutting  instruments  in  steel,  at  least  6  or  8 
long-handled  instruments  should  be  constructed,  the  balance 
of  the  work  being  done  on  annealed  brass  wire,  13-gauge, 
cut  to  6-inch  lengths.  The  student  should  make  a  complete 
set  of  the  hand  cutting  instruments  as  used  in  the  operative 
clinic  of  the  college. 

Technic  Work  in  Steel.    Instruments  required. — 

1.  Blowpipe,  foot  bellows  and  tubing,  or  Bunsen 
burner 

2.  Bench  vise 


MAKING    STEEL   EXCAVATORS    AND    CHISELS  87 

3.  Pliers  (round-nose  and  flat-nose) 

4.  Carborundum  stones  and  chuck  for  lathe 

5.  Arkansas  stone 

6.  Anvil 

7.  Hammer 

8.  Metal  flle 

9.  Instrument  gauge 

10.  Felt  cones  and  brush  wheels  for  lathe 

11.  Emery  paper  and  pohshing  powders. 

Directions  for  Making  Steel  Excavators  and  Chisels 

1.  Annealing. — Select  the  blank  of  proper  size  and  with 
the  blowpipe  or  Bunsen  burner  heat  the  point  and  shank  to 
ftdl  cherry  red  and  allow  to  cool  slowly.  This  anneals  it  and 
makes  it  soft  and  pliable. 

2.  Place  the  instrument  to  be  duplicated,  or  a  picture  of 
it,  together  with  a  memorandum  of  its  formula,  before  you. 

3.  With  the  millimeter  gauge  see  if  that  portion  to  be  made 
into  the  blade  will  need  any  change  in  form  or  dimensions;  if  so, 
procure  the  needed  change  with  hammer  and  an\dl  or  the  file. 

4.  If  necessary,  file  the  shank  down  to  the  proper  measure- 
ment and  taper. 

5.  Angling. — Bend  the  shank  by  means  of  the  pliers  till 
the  proper  angles,  as  mon-angle,  bin-angle,  triple-angle, 
contra-angle,  etc.,  are  procured,  as  indicated  by  its  formula, 
verifying  them  with  the  instrument  gauge  and  by  comparing 
with  the  model  to  be  duplicated. 

6.  Beveling. — File  the  cutting  edge  of  the  blade  to  the  pro- 
per bevel,  verifying  all  dimensions  with  the  millimeter  gauge. 

7.  Preliminary  Polish. — Remove  all  file  marks  with  fine 
emery  paper,  then  take  to  the  lathe  and  give  a  high  polish, 
first  using  pumice  on  a  felt  cone  or  wheel  and  later  whiting 
and  water. 


88  INSTRUMENTS   AND   APPLIANCES 

8.  Hardening. — Cover  with  soap,  heat  to  a  full  cherry 
red  color  and  plunge  immediately  in  cold  water.  Be  careful 
not  to  overheat  the  blank.  Better  underheat  it,  for  if  over- 
heated the  carbon  is  burned  out  and  the  instrument  will  not 
take  a  fine  edge. 

9.  Testing.^Ttst  with  a  file  for  proper  hardness.  If  the 
file  attacks  the  metal  it  is  too  soft.  If  this  is  the  case,  reheat 
as  before  and  again  plunge. 

10.  Secondary  Polish. — Polish  again  according  to  the 
directions  already  given. 

11.  Tempering. — Place  the  shank  of  the  instrument  in 
the  flame  and  heat  to  a  faint  yellow  or  straw  color,  plunging 
immediately  in  cold  water  or  other  media  as  indicated. 

12.  Tertiary  Polish. — Polish  again  to  remove  the  oxides 
formed  on  the  surface,  so  that  the  colors  may  again  be  seen 
to  appear  in  case  of  subsequent  tempering. 

13.  Spring  Temper  for  Shank. — Cover  with  soap  and 
place  the  blade  of  the  instrument  in  contact  with  a  hammer  or 
some  other  large  piece  of  metal,  so  that  it  will  conduct  away 
the  heat  and  prevent  drawing  the  temper  already  given  the 
blade.  Place  that  portion  of  the  shank  back  of  where  the 
temper  is  required  in  the  flame,  heat  and  watch  closely  for 
the  blue  color,  on  the  appearance  of  which,  plunge  immediately 
as  before. 

14.  Sharpening  and  Final  Polish. — Again  polish,  and 
sharpen  the  blade  for  use. 

Technic  Work  in  Brass. — If  the  instruments  are  made  in 
brass,  practically  the  same  procedures  are  followed,  except 
that  no  hardening  or  tempering  is  required  and  the  polish- 
ing is  done  only  on  completion  of  the  work.  The  brass 
should  be  first  annealed,  when  it  is  ready  for  the  various 
manipulations  (Fig.  124). 


TECHNIC   WORK   IN  BRASS 


89 


Fig.  124. — Set  of  instruments  made  from  brass  wire  as  used  at  Northwestern 
University  Dental  School.     Courtesy  of  Dr.  Fred.  W  Gethro. 


CHAPTER  III 
PREPARATION  OF  CAVITIES 

Causes  of  Decay. — Cavities  occur  in  teeth  as  a  result  of 
decay  beginning  on  their  surface.  Decay  is  the  result  of  the 
fermentation  of  food  debris.  Fermentation  is  a  decomposi- 
tion of  carbohydrates  (starches,  sugars,  etc.).  Food  debris 
accumulates  because  of  neglect  in  the  application  of  the 
ordinary  rules  of  cleanliness  to  the  care  of  the  teeth.  Fer- 
mentation of  food  debris  is  due  to  the  constant  presence 
of  germs  in  the  mouth.  The  action  of  certain  of  these  germs 
on  the  fermentable  material  produces  lactic  acid.  Lactic 
acid  dissolves  out  the  lime  salts,  of  which  the  major  part  of 
the  tooth  is  composed.  Other  germs,  constantly  present, 
liquefy  the  organic  material,  which  constitutes  the  remainder 
of  the  tooth.     The  result  is  a  cavity  of  decay. 

Definition.— By  "preparation  of  cavities"  is  meant  those 
procedures  incident  to  the  removal  of  decay  and  the  shaping 
of  the  cavity,  so  that  when  filled,  the  tooth  will  be  restored, 
as  far  as  possible,  to  its  original  form  and  strength,  and  be 
immune  from  future  decay  in  the  same  location. 

Nomenclature. — A  system  of  words,  sounds  or  signs  by 
which  individuals  of  the  same  race,  profession,  or  calling,  are 
enabled  to  understand  each  other.  The  profession  of  dentis- 
try has  a  nomenclature  of  its  own.  A  study  of  the  nomencla- 
ture of  cavity  preparation  is  essential  to  an  understanding 
of  the  contents  of  the  following  chapter, 

.90 


CAVITY   NOMENCLATURE 


91 


Angle. — The  union  of  two  surfaces  along  a  definite  line 
{line  aiii^le)  or  of  three  surfaces  at  a  point  {point  angle). 

Cavo-surface  Angle. — The  angle  formed  by  the  junction 
of  the  walls  of  the  cavity  with  the  surface  of  the  tooth. 

Axial  Line  Angle. — A  line  angle  running  parallel  with  the 
long  axis  of  the  tooth. 

Pulpal  Line  Angle. — One  running  horizontally  to  the  long 
axis  of  the  tooth. 

Wall. — One  of  the  internal  boundaries  of  a  cavity. 

Margin. — The  junction  of  the  walls  of  a  cavity  with  the 
surface  of  a  tooth. 

Marginal  Outline. — The  shape  of  the  cavity  along  its 
margins. 

Dento-enamel  Junction. — The  Kne  representing  the  junc- 
tion of  the  enamel  and  dentin. 

The  nomenclature  of  cavity  preparation  followed  and  now 
considered  official  is  that  adopted  by  the  Institute  of  Dental 
Pedagogics,  from  the  report  of  a  committee  of  which  Dr. 
Thomas  E.  Weeks  was  Chairman,  as  follows: 

CAVITY  NOMENCLATURE 

All  that  is  to  be  said  in  describing  cavity  preparation  can 
be  expressed  by  the  use  of  the  following  nouns  and  adjectives : 


Cavity 
Wall 
Margin 
Plane 


Surface 
Angle 
Thirds 
Embrasure 


Labial 
Buccal 
Lingual 
Proximal 


Mesial 
Distal 
Incisal 
Occlusal 


Gingival 
Axial 
Pulpal 
Subpulpal 


Cavity  Names 


Cavities  in  the  teeth  take  the  names  of  the  surfaces  in 
which  they  occur. 


92 


PREPARATION    OP    CAVITIES 


Simple 


Cavity 


Complex       < 


Labial 

Buccal 

Lingual 

Mesial 

Distal 

Occlusal 

Mesio-incisal 

Disto-incisal 

Mesio-labial 

Disto-labial 

Mesio-lingual 

Disto-lingual 

Mesio-occlusal 

Disto-occlusal 

Linguo-occlusal 

Bucco-occlusal 

Mesio-distal-occlusal 

(Other  combinations 

by  the  same  rule) 


Wall  Names 


Labial 

Buccal 

Incisal 

Occlusal 

Lingual 

Mesial 

Distal 

Gingival 

Axial 

Pulpal 

Subpulpal 

Rule. — Cavity  walls  take  the  names  of  the  surfaces  of  the  tooth  which  they 
approach. 


That  waU  of  a  cavity  in  an  axial  surface  of  a  tooth  that 
covers  the  pulp  is  called  the  axial  wall.  If  the  cavity 
is  extended  to  include  the  pulp  chamber  this  wall  takes 
the  name  of  the  wall  of  the  pulp  chamber.  The  \  Wall  { 
bottom  or  iloor  of  occlusal  cavities  is  called  the  piilpal 
wall.  If  extended  to  include  the  pulp  chamber  it 
becomes  the  subpulpal  wall. 


CAVITY   NOMENCLATURE 


93 


Angles 


Line  (Axial) 


Line  (Pulpal) 


Point 


Angles  (Simple  Cavities) 

Mesio-buccal 

Mesio-lingual 

Disto-buccal 

Disto-lingual 

Bucco-axial 

Linguo-axial 

Mesio-axial 

Disto-axial 

Bucco-pulpal 

Linguo-pulpal 

Mesio-pulpal 

Disto-pulpal 

Bucco-gingival 

Linguo-gingival 

JMesio-gingival 

Disto-gingival 

Axio-gingival 

(and  combinations 

with  occlusal  wall) 

Mesio-bucco-pulpal 

Disto-bucco-pulpal 


'  Occlusal  cavities 


>  Axial  surface  cavities 


•  Occlusal  cavities 


>  Axial  surface  cavities 


]\Iesio-lingual-pulpal 
Disto-linguo-pulpal 


Point  Angles  (the  union  of  three-line  angles)  take  their 
names  from  the  surfaces  forming  them.  In  occlusal  ca\aties 
there  are  four. 

In  complex  cavities  on  axial  surfaces  there  is  another 
horizontal  line  angle,  i.e.,  in  axial  cavities  combined  with 
occlusal,  the  one  formed  by  union  of  the  axial  and  the 
pulpal  wall— axio -pulpal. 


94 


PREPARATION    OF    CAVITIES 


Division  into  Thirds 

Cavities  may  be  divided  into  thirds,  for  convenience  in 
description,  as  teeth  are  divided. 


Names  of  Margins 

Mesial 

Distal 

Buccal 

Labial 

Lingual 

Incisal 

Occlusal 

Gingival 

Nomenclature  of  Simple  Cavities 


Margins 


WaUs 


Line  angles 
(longitudinal) 


Line  angles 
(transverse) 


Cavo-surface 
angles 


Point  angles 


Margins 


Occlusal  Cavities 

Mesial 

Distal 

I   Buccal 

Lingual 

Pulpal 

Mesio-buccal 
Mesio-lingual 
Disto-buccal 
Disto-lingual 


Mesio-pulpal 
Disto-pulpal 
Linguo-pulpal 
Bucco-pulpal 

Mesio-occlusal 

Disto-occlusal 

Bucco-occlusal 

Linguo-occlusal 

Mesio-bucco-pulpal 

Disto-bucco-pulpal 

Mesio-linguo-pulpal 

Disto-linguo-pulpal 

Mesial 

Distal 

Buccal 

Lingual 


Line  angles 
(longitudinal) 


Line  angles 
(transverse) 


•  Cavo-surface 
angles 


Point  angles 


Margins 


Labial,  Buccal  or  Lingual  Cavities 
Mesial 
Distal 
Walls  \   Gingival 

Occlusal  or  incisal 
Axial 

Mesio-axial 
Disto-axial 

Mesio-occlusal 

Disto-occlusal 

Mesio-gingival 

Disto-gingival 

Occluso-axial 

Gingivo-axial 

Based  on  the  same 
rule  as  for  occlu- 
sal cavities 
Mesio-axio-gingiva] 
Disto-axio-gingival 
Mesio-axio-occlusal 
Disto-axio-occlusal 
Mesial 
Distal 
Gingival 
Occlusal  or  incisal 


CAVITY    NOMENCLATURE 


95 


Pit  and  fissure  (no 
extension  for  pre- 
vention) . 


Cavities.  < 


Smooth  surface  (ex- 
tension for  preven- 
tion). 


Simple  cavities  on  proximal  surfaces  have  the  same 
number  of  walls,  angles,  and  margins  as  those  on  other  axial 
surfaces,  and  are  named  similarly. 

With  this  basis  all  cavities,  however  complex,  may  be 
easily  named  and  described. 

CAVITY  CLASSIFICATION,  NOMENCLATURE.  AND  PREPARATION ' 

Classification 
Cavities     in    the    lingual    surfaces    of    upper 

incisors. 
Cavities  in  occlusal  surfaces  of  bicuspids  and 

molars. 
Cavities    in    the    occlusal    two-thirds    of    the 

buccal  and  lingual  surfaces  of  molars. 
Cavities  in   the  gingival   third  of   the  labial, 

buccal,  and  lingual  surfaces. 
Cavities  in  pro.ximal  surfaces  of  incisors  and 

cuspids  which  do  not  involve  the  mesial  or 

distal  incisal  angle. 
Cavities  in  proximal  surfaces  of  incisors  and 

cuspids    which    do    involve    the    mesial    or 

distal  incisal  angle. 
Cavities  in  the  pro.ximal  surfaces  of  bicuspids 

and  molars. 

Note. — Ca^dties  occurring  in  consequence  of  arrested 
development  are  not  included. 

STEPS  IN  CAVITY  PREPARATION 

1.  Establish  the  outline  form. 

2.  Remove  the  decay. 

(a)  Convenience  form. 

(b)  Resistance  form. 

(c)  Retention  form. 

4.  Bevel  and  polish  the  enamel  margins. 

5.  Perform  the  toilet  of  the  cavity. 

*The  above  tables  on  cavity  nomenclature  were  published  in  the  American  Text- 
book of  Operative  Dentistry,  to  the  publishers  of  which  acknowledgment  is  here 
extended. 


3.  Give  the  cavity  proper  form 


g6  PREPARATION   OF   CAVITIES 

I.  ESTABLISH   THE   OUTLINE   FORM.— Carry   the 

marginal  outline  to  the  location  which  it  will  occupy  on  the 
completion  of  the  cavity.  This  procedure,  and  not  the  re- 
moval of  the  decay,  should  be  the  first  thought  to  enter  the 
student's  mind,  for  reasons  which  will  be  understood  better 
as  he  progresses. 

Rule  I. — Extend  the  margins  until  solid  tooth  structure, 
free  from  decay,  is  reached. 

Rule  2. — Leave  no  overhanging  enamel  margins  unsupported 
by  dentin.  The  enamel  of  the  tooth  is  extremely  brittle,  owing 
to  its  histological  structure,  and  depends  for  its  strength  on 
the  support  which  it  receives  from  the  underlying  dentin. 

Rule  3. — In  fissure  cavities,  extend  the  margins  to  include  the 
entire  fissure.  Pits  and  fissures  are  extremely  liable  to  decay, 
and  if  this  rule  is  not  followed  decay  is  liable  to  occur  in  that 
part  of  the  fissure  not  included  in  the  cavity,  with  a  conse- 
quent undermining  of  the  filling. 

Rule  4. — Extend  the  margins  of  cavities  approaching  closely 
to  deep  developmental  grooves,  to  include  the  grooves  for  reasons 
of  strength,  as  well  as  for  the  reason  given  in  Rule  3. 

Rule  5. — Unite  two  cavities  approaching  closely  to  each  other, 
to  prevent  the  leaving  of  a  weak  ridge  of  tooth  structure 
between  them. 

Rule  6. — Extend  the  gingival  margins  of  cavities  occurring  in 
the  gingival  third  of  labial,  buccal  and  lingual  surfaces  under  the 
free  margin  of  the  gum,  where  they  will  be  less  liable  to  decay. 

Rule  7. — In  proximal  cavities  extend  the  labial,  buccal  and 
lingual  walls  well  out  into  the  embrasures,  into  areas  where  they 
will  be  less  likely  to  decay;  the  incisal  or  occlusal  margins  be- 
yond the  contact  point;  and  the  gingival  margins  under  the  free 
margin  of  the  gum.  The  extension  of  these  margins,  as  laid 
down  in  this  rule,  follows  the  law  known  as  "extension  for 
prevention,"  which  requires  a  brief  explanation  at  this  time. 


EST.'VBLISHING    THE   OUTLINE   FORM  97 

Extension  for  Prevention 

Proximal  surfaces  of  the  teeth  are  much  more  subject  to 
decay  than  other  portions,  because  food  and  germs  accumu- 
late more  readily  here,  and  are  less  easily  removed.  This 
being  the  case,  if  the  margins  of  cavities  are  left  in  these 
vulnerable  areas,  they  will  be  much  harder  to  keep  clean, 
and  hence  decay  is  likely  to  recur  readily.  Recognizing  this 
fact,  it  is  the  accepted  practice  to  extend  the  margins  of  cavi- 
ties, when  they  occur  in  these  areas,  by  cutting  away  enough 
of  the  tooth  substance  to  carry  them  out  to  locations  where  the 
food  is  not  so  liable  to  deposit,  and  where  they  may  be  more 
readily  cleansed.  The  food  does  not  accumulate  under  the 
gum  margin  so  much  as  it  does  a  short  distance  occlusally  to 
this  point,  hence  the  reason  for  extension  of  the  gingival 
margins.  Food  accumulates  very  readily  and  frequently 
remains  just  gingivally  to  the  contact  points  of  two  approxi- 
mating teeth,  and  in  order  to  obviate  the  necessity  of  lea\dng 
the  incisal  or  occlusal  margins  within  this  vulnerable  area, 
these  margins  are  carried  beyond  this  point  down  toward  the 
incisal,  or  occlusal  surface,  where  the}-  can  be  more  readily 
cleansed.  Buccal  and  lingual  margins,  for  the  same  reasons, 
are  extended  out  into  the  embrasures  for  a  certain  distance, 
depending  on  the  con\'exity  of  the  tooth  surface  and  the  char- 
acter of  approximation. 

There  are  many  conditions,  physical  and  otherwdse,  which 
modify  the  operation  of  extension  for  prevention  in  the  mouth. 
In  his  technic  course,  the  student  will  learn  how  to  prepare 
typical  cavities  according  to  the  extension  for  prevention 
theory,  which  was  promulgated  by  G.  V.  Black,  although 
he  did  not  originate  the  term  by  which  it  is  known.  When  he 
begins  to  operate  in  the  mouth  and  advance  further  into  the 
study  of  the  causes  of  decay  and  its  prevention,  these  condi- 
7 


98  PREPARATION   OF    CAVITIES 

tions  will  be  more  fully  understood.  At  first,  his  tendency 
will  be  to  extend  his  margins  too  far,  at  the  sacrifice  of  too  much 
good  tooth  structure,  and  he  should  learn  to  guard  against 
this  evil. 


Drawings 

Draw  the  typical  outline  form  of  the  following  cavities. 
I.  Fissure  cavity  on  the  occlusal  surf  ace  of  4  or  5  running 
full  length  of  the  occlusal  groove  (Fig.  125). 

M 

M 

B 

B     '  ■"' 


Fig.  125. — Outline    form.     Occlusal  Fig.  126. — Outline  form.     Occlu- 

cavity  on  the  upper  first  bicuspid.  sal  cavities  on  the  lower  first  and  sec- 

ond bicuspids. 

2.  Pit  and  fissure  cavity  on  the  occlusal  surface  of  4  and 
5  ,  occupying  the  mesial  and  distal  pit  in  4  and  running  full 

length  of  the  groove  in  5  (Figs.  126  and  127).  In  5  there  are 
two  typical  forms  depending  on  the  shape  of  the  occlusal 
groove. 

3.  Cavity  in  central  and  distal  fossae  of  6,  7  and  _8_(Fig. 
128).  If  the  oblique  ridge  is  left  very  weak,  unite  the  cavities. 
If  _8_  has  three  cusps,  the  typical  form  will  appear  as  in 
Fig.  129. 


ESTABLISHING   THE    OUTLINE    FORM 


99 


4.  Cavity  on  the  occlusal  surface  of  6   (Fig.  130). 

5.  Cavity  on  the  occlusal  surface  of  7  (Fig.  130).     On  8 
the  outline  form  will  appear  like  that  for  6  ,  or  7  ,  depending 
on  the  form  of  the  tooth. 

6.  Mesial  cavity  on    1   (Fig.  131).     The  outline  form  for 
proximal  ca\ities  in  the  six  an- 
terior teeth,  upper  or  lower,  is  M 

about  the  same. 

Technic    for   Establishing    the 

Outline  Form. 

(i)  On  Enlarged  Plaster 
Teeth. — (a)  With  a  pencil  draw 
the  outline  form,  (b)  With 
vulcanite   chisels    and   scrapers 


B 


M 


B 


Fig.  127. — Outline  form.  Occlu- 
sal cavity  in  a  lower  second  bicus- 
pid \\-ith  three  cusps. 


Fig.  128. — Outline  form.  Occlusal 
cavities  in  upper  molars.  In  the  second 
molar  the  two  cavaties  have  so  under- 
mined the  oblique  ridge  that  it  has 
been  necessarj'  to  unite  them. 


remove  enough  of  the  plaster  to  estabHsh  a  definite  ca\ity. 

(2)  On  the  Technic  Block. — (a)  With  a  pencil  draw  the 
outline  form,  (b)  With  chisels  and  excavators  remove  enough 
of  the  tooth  substance  to  estabhsh  a  definite  cavity. 

(3)  On  Extracted  Teeth. — (a)  With  a  pencil  draw  the 
outline  form,     (b)  With  the  chisel  cut  away  the  overhanging 


lOO 


PREPARATION   OF   CAVITIES 


and  unsupported  enamel,  (c)  If  necessary  to  extend  further, 
first  remove  the  underlying  dentin  with  excavators  (hoes, 
hatchets  and  spoons)  and  then  chisel  the  enamel  the  desired 
distance. 

2.  REMOVE  THE  DECAY.— Complete  removal  of  decay 
is  essential.     If  the  minutest  portion  be  left  unsterilized,  decay 
wiU  continue,  producing  irritation  of  the  pulp  via  the  dentinal 
fibrillae  and  finally  result  in  the 
undermining  of  the  filling.  %J^ 

Technic  for  Removing  Decay. 

I.  On  Extracted  Teeth. — (a) 
For  removal  of  soft  decay  use 
the  spoons  and  discoids.  (b) 
For  hard  decay  use  hatchets 
and  hoes. 


M 


B 


B 


Fig.  129. — Outline  form.  Occlu- 
sal cavity  in  an  upper  third  molar 
with  three  cusps. 


FiG_.  130. — Outline  form.  Occlu- 
sal cavities  in  the  lower  first  and  sec- 
ond molars. 


3.  GIVE  THE  CAVITY  FORM.— (a)  Convenience  Form. 

The  shaping  of  the  cavity  in  such  a  manner  that  it  may  be 
most  conveniently  seen  and  approached  with  instruments. 
If  the  cavity  be  of  difi&cult  access,  owing  to  its  location,  the 
sKght  extension  of  a  margin  is  frequently  admissible  for  this 
purpose.     The  extension  of  the  labial  margins  of  proximal 


GIVING   THE   CAVITY  FORM  lOI 

cavities  for  convenience  is  not  admissible,  as  this  would  result 
in  too  great  a  display  of  filling  material.  In  every  instance 
where  it  becomes  necessary  to  extend  margins  for  convenience 
form,  the  extension  is  made  at  the  expense  of  the  lingual 
margin,  the  filhng  being  packed  in  that  case  largely  from  the 
lingual  side.  The  display  of  extensive  gold  operations  in  the 
front  teeth  is  an  offence  against  the  esthetic  sensibilities  of  all 
refined  individuals,  and  a  sure  sign  of  a  depraved  taste  on  the 
part  of  both  patient  and  operator. 


.a 


Fig.  131. — Outline  form.     Mesial  cavity  an  the  upper  central  incisor. 

For  convenience  in  starting  gold,  the  point  angles  to  be 
described  under  "retention  form"  are  frequently  deepened, 
or  made  more  acute,  this  procedure,  then,  being  really  a 
convenience  form  (see  Fig.  162). 

(b)  Resistance  Form. — The  so  shaping  of  the  walls  of 
the  cavity  that  they  may  be  best  enabled  to  withstand  the 
stress  brought  to  bear  on  the  filling  during  the  act  of  mastica- 
tion. In  mechanics,  the  general  form  of  a  cavity  which  is 
to  receive  an  inlay  is  the  box  or  simple  mortise.  This  general 
idea  is  applied  in  preparing  cavities  in  teeth.     In  this  form, 


I02  PREPARATION   OF    CAVITIES 

all  of  the  walls  of  the  mortise  are  on  plain  or  straight  lines, 
joining  each  other  at  definite  line  and  point  angles. 


Fig.  132.  Fig.  133.  Fig.  134. 

Fig.  132. — Simple  mortise  on  one  surface. 

Fig.  133. — Simple  dovetail  mortise  on  one  surface.  The  plaster  block  has  been 
sawed  in  half  to  show  the  inside  of  the  cavity,  which  is  dovetailed  on  two  opposite 
surfaces. 

Fig.  134. — Simple  mortise  form  involving  two  surfaces. 


Fig.  135.  Fig.  136.  Fig.  137. 

Fig.  135. — Method  of  dovetaihng  the  simple  mortise  involving  two  surfaces,  thus 
making  it  retentive  in  form. 

Fig.  136. — Auxiliary  mortise  (step  form). 
Fig.  137. — Compound  dovetail  mortise. 

Technical  Exercises 

On  six  cubes  of  plaster  of  Paris  2  inches  square,  prepare 
the  six  forms  of  mortise.  Study  the  line  and  point  angles 
in  these  imaginary  cavities. 


GIVING    THE    CAVITY    FORM 


103 


Rules  for  obtaining  resistance  form. 

Rule   1.      Ill   llic  shaping  of  all  sim])lc  cavities,   use  ihe 
simple  mortise  form,  or  some  modification  of  it.     Examples 


Fig.  138.  Fig.  139. 

Fig.   138. — Cavity  in  the  cenLrd  fossa  of  a  right  upper  first  molar  tooth. 
Fig.   139. — Cavity  involving  the  occlusal  groove  on  an  upper  bicuspid. 

illustrating  the  application  of  the  simple  mortise  to  cavity 

formation  are  seen  in  Figs.  138,  139,  140,  141,  142  and  143. 

Rule  2. — In  proximo-occlusal  cavities  on  bicuspids  and 


Fig.  140.  Fig.  141.  Fig.  142. 

Fig.  140. — Cavity  in  the  gingival  third  of  the  labial  surface  of  a  right  upper  central 
incisor. 

P'ig.  141. — .\nother  form  of  prci)aration  for  cavities  located  on  the  gingival  third. 
Fig.  142. — Cavity  involving  the  lingual  pit  of  a  left  upper  lateral  incisor. 

molars,  where  the  strength  of  buccal  and  lingual  walls  will 
permit  and  there  is  no  decay  on  the  occlusal  surface,  use  the 
simple  mortise  form  involving  two  surfaces  (see  Fig.  144). 


I04 


PREPARATION   OF   CAVITIES 


Rule  3. — In  proximo-occlusal  cavities  in  other  cases  than 
the  above,  use  the  double,  compound  or  auxiliary  mortise 

form  (step  form)  (Fig.  145  and  146). 


Fig.  143.  Fig.  144. 

Fig.  143. — "Gingival  third"  cavity  on  the  buccal  surface  of  a  bicuspid. 

Fig.  144. — Application  of  the  simple  dovetail  mortise  form  to  a  disto-occlusal 
cavity  in  an  upper  molar,  where  the  occlusal  surface  presents  good  union  of  enamel 
plates  and  is  free  from  decay. 

Rule  4. — In  proximo-incisal  cavities,  where  the  loss  of  the 
mesio-  or  disto-incisal  angle  is  not  extensive  and  where  the 


Fig.  145.  Fig.  146. 

Fig.  145. — Application  of  the  compound  mortise  form  to  a  mesio-occlusal  cavity 
on  an  upper  bicuspid. 

Fig.  146. — Step  form  in  a  mesio-occlusal  cavity  on  an  upper  molar. 

stress  of  mastication  is  not  great,  use  the  simple  mortise  form. 

(Figs.  149,  150,  151.) 

Rule  5. — In  proximo-incisal  cavities,  when  the  involvement 


GIVING    THE    CAVITY   FOKM  I05 

of  the  incisal  ecl^c  is  exlensive,  use  the  double,  compound  or 
auxiliary  mortise  form,  either  in  the  shape  of  an  incisal  step 
or  a  lingual  step  form  (see  Figs.  152,  153,  154,  155  and  159). 
Technic  for  Obtaining  Resistance  Form. 

Use  hatchet  and  hoe  excavators  and  straight-edged  chisels. 
All  of  these  cut  plane  surfaces,  joining  at  definite  angles,  and 
give  the  box  or  mortise  form. 

I.  Pit  and  Fissure  and  "Gingival  Third"  Cavities. — With 
the  excavators  and  chisels  flatten  the  pulpal  or  axial  wall 
of  the  ca\'ity,  and  true  up  the  lateral  walls  until  they  are  plane 


Fig.  147.  Fig.  148. 

Fig.   147. — Ca\-ity  running  full  length  of  the  lingual  groove  on  an  upper  molar. 
Fig.  1 4$. — Cavity  involving  the  central  and  distal  fossas  and  lingual  groove  on  an 
upper  molar. 

siufaces,  parallel  with  each  other  and  joining  with  the  pulpal 
or  axial  wall  (the  seat)  at  definite  angles  (see  Figs.  138,  139, 
140,  141,  T42,  143,  147  and  148). 

2.  Cavities  in  the  Proximal  Surfaces  of  the  Incisors  and 
Cuspids  not  Involving  the  Angle. — (a)  With  the  hatchets,  hoes 
and  chisels,  flatten  the  gingival  and  axial  walls,  making  a 
definite  line  angle  at  their  junction,  (b)  Bring  the  axial, 
gingival,  labial  and  lingual  walls  together  at  two  definite 
point  angles  (labio-gingivo-axial  and  lingo-gingivo-axial  point 
angles) .  (c)  Join  the  labial  and  lingual  walls  together  at  a  def- 
inite point  angle  at  the  incisal  portion  of  the  cavity,  the  re- 


io6 


PREPARATION    OP    CAVITIES 


sultant  form  being  triangular  in  shape,  with  three  definite 
point  angles  (Figs.  149^  150  and  151). 

3.  Cavities  in  Proximal  Surfaces  of  Incisors  and  Cuspids 
Involving  the  Angle. — (a)  If  the  simple  mortise  form  is  adopted 
the  procedure  is  practically  the  same  as  that  described  in 
the  preceding  paragraph,  consisting  in  flattening  the  gingival 
and  axial  walls  and  joining  them  at  a  definite  line  angle,  the 
gingivo-axial  line  angle.     The  resistance  form  is  afforded  by 


Fig.  149.  Fig.  150.  Fig.  151. 

Fig.  149. — Mesial  cavity  on  an  upper  central  incisor  showing  the  flat  gingival  wall. 
Labial  view. 

Fig.  150. — Lingual  view  of  the  same  cavity  shown  in  Fig.  149. 

Fig.  151. — Cavity  shown  in  Figs.  149  and  150  seen  from  a  different  aspect.  The 
triangular  form  with  three  point  angles  is  noticeable. 

the  flat  gingival  wall,  (b)  Incisal  step  form.  After  obtaining 
the  form  as  described  in  "(a),"  with  a  chisel  (except  in  ex- 
tracted teeth)  cut  a  step  about  one-half  or  two-thirds  the 
distance  across  the  cutting  edge  of  the  tooth,  exposing  the 
imaginary  dentin  and  removing  as  little  of  the  labial  plate 
of  the  imaginary  enamel  as  the  tooth  will  allow.  Then, 
with  a  hoe,  remove  the  imaginary  dentin  between  the  labial 
and  lingual   enamel  plates,  cutting   mesio-distally,  until    a 


GIVING    THE   CAVITY   FORM 


107 


Fig.  152.  Fig.  153. 

Fig.  152. — Mesio-incisal  cavity  on  an  upper  central  incisor.  Labial  view.  An 
effort  has  been  made  to  preserve  as  much  of  the  labial  enamel  plate  as  conditions 
will  permit. 

Fig.  153. — Lingual  view  of  the  cavity  shown  in  Fig,  152.  The  flat  gingival  wall 
is  well  shown;  also  the  cutting  of  the  incisal  step  more  at  the  expense  of  the  lingual 
wall  in  order  to  preserve  the  labial  enamel  plate. 


Fig.  154.  Fig.  155. 

Fig.  154. — Lingual  step  form' in  an  upper  lateral  incisor.  The  gingival  wall, 
instead  of  being  made  flat,  has  been  cut 'to  follow  the  curvature  of  the  gingival 
line  somewhat,  in  order  to  provide  a  better'seat  and  anchorage  for  the  filling. 

Fi<^-  155- — Labial  view  of  the  mesio-incisal  cavity  with  lingual  do\etail,  shown  in 
Fig-  '54- 


io8 


PREPARATION    OP    CAVITIES 


groove  is  formed.  Now,  with  the  chisel,  cut  away  more  of 
the  Hngual  enamel  plate,  and  then  with  the  hoe  deepen  the 
groove,  continuing  thus,  always  cutting  at  the  expense  of  the 
lingual  side,  till  the  step  form  is  complete  and  will  allow  a 
sufficient  bulk  of  filling  material  for  strength  (Figs.  152  and 
153)-  (9)  Lingual  step  form.  Where  the  tooth  is  too  thin, 
labio-lingually,  to  warrant  the  incisal  step,  prepare  an 
auxiliary  mortise  form  on  the  lingual  surface  of  the  tooth 
with  the  chisels,  hoes  and  hatchets,  as  illustrated  in  Figs. 
154  and  155.     The  floor  of  this  step  is   made  flat  and  the 


Fig.  156.  Fig.  157. 

Fig.  156. — Simple  cavity  on  the  proximal  surface  of  a  bicuspid.     A  form  which  is 
seldom,  if  ever,  admissible. 

Fig.  157. — Proximo-occlusal  cavity  an  an  upper  bicuspid.     Step  form. 


lateral  walls  plane  surfaces,  joining  the  floor  at  definite  line 
angles. 

4.  Cavities  in  Proximal  Surfaces  of  Bicuspids  and  Molars. 

— Extend  the  cavity  through  the  marginal  ridge  on  to  the 
occlusal  surface.  When  the  occlusal  grooves  and  fossae  are 
perfect  and  the  strength  of  the  buccal  and  lingual  walls  per- 
mits, the  simple  mortise  form  involving  the  proximal  and 
occlusal  surfaces  maybe  adopted  (Rule  2)  (see  Figs.  135  and 
[44).  In  the  majority  of  cases,  however,  the  cavity  is  made 
to  include  the  occlusal  groove  or  fossa,  utilizing  the  com- 


GIVING   THE   CAVITY   FORM 


109 


pound  mortise  or  step  form,  (a)  Simple  mortise  form.  Jn 
natural  teeth,  remove  the  dentin  underlying  the  marginal 
ridge  with  the  hoe  or  hatchet  excavator,  and  then  chisel 
away  the  enamel,  carrying  the  cavity  well  over  on  to  the 
occlusal  surface.  In  other  cases,  chisel  away  the  marginal 
ridge.  With  hoes  and  hatchets  flatten  and  render  plane 
the  gingival,  axial,  buccal  and  lingual  walls,  joining  them 
along  definite  line  angles,  and  giving  the  cavity  the  typical 
box  form    (Fig.    144).     (b)  Compound  mortise  form.     (Step 


Fig.  158.  Fig.  159. 

Fig.  158. — Proximo-occlusal  cavity  on  a  bicuspid.    Compound  mortise  or  step  form. 
Fig.  159. — Another  ^dew  of  the  cavity  shown  in  Figs.  152,  153. 

form.)  Extend  the  cavity  in  the  form  of  a  step  by  means 
of  the  chisels,  hatchets  and  hoes,  the  full  length  of  the 
occlusal  groove  (bicuspids)  or  to  include  the  entire  central 
or  distal  fossa  (molars).  Flatten  the  gingival  wall  (the 
seat)  as  before,  make  the  buccal  and  lingual  walls  parallel 
with  each  other  and  joining  the  gingival  wall  at  right  angles. 
Make  a  definite  line  angle  at  the  junction  of  the  gingival  and 
axial  walls  (gingivo-axial)  and  definite  point  angles  (bucco- 
gingivo-axial  and  Ungo-gingivo-axial)  at  the  buccal  and  lingual 


no 


PREPARATION   OP   CAVITIES 


termination  of  this  line.  Flatten  the  top  of  the  step,  the 
pulpal  wall,  and  cut  that  portion  of  the  cavity  to  the  box 
form  with  its  line  and  point  angles  (Figs.  145,  146,  157  and 

158).  •  ^ 

Seat. — In  simple  cavities  the  bottom  or  floor  of  the  cavity, 

either  the  axial  or  pulpal  wall. 

Step. — The  auxiliary  portion  of  the  compound  mortise 
form,  consisting  of  the  axial  and  pulpal  walls  in  complex 
cavities. 


Fig.  160.  Fig.  i6i. 

Fig.  160.— Step'formln  a  disto-incisal  cavity  on  an  upper  cuspid. 
Fig.  161. — ^Labial  view  of  a  mesio-incisal  cavity  on  an  upper  cuspid  showing  flat 
gingival  wall. 

(c)  Retention  Form. — The  so  shaping  of  the  cavity  that 
the  filling  may  be  enabled  to  resist  tipping  or  lifting  stress, 
(i)  In  pit  and  fissure  and  gingival  third  cavities,  where  the 
depth  of  the  cavity  is  greater  than  its  diameter,  no  extra 
retention  form  is  needed,  the  filling  being  retained  by  its 
contact  with  the  lateral  walls  of  the  cavity.  The  accomphsh- 
ment  of  this  condition,  though,  is  not  often  admissible,  owing 
to  the  proximity  of  the  pulp.     In  the  majority  of  cases,  then, 


GIVING    THE    CAVITY    FORM  III 

retention  is  provided  for  by  transforminjjj  the  simple  mortise 
form  into  the  dovetail  mortise  form  (Fig.  133).  In  doing 
this,  one,  or  at  most  two,  opposite  walls  of  the  cavity  are 
slightly  dovetailed.  (2)  In  proximal  cavities  on  incisors  and 
cuspids  not  involving  the  angle,  retention  is  provided  for  by 
making  more  acute  the  labio-gingivo-axial,  lingo-gingivo-axial 
and  the  incisal  point  angles  (Figs.  149  and  151).  (3)  In 
proximal  cavities  on  incisors  and  cuspids  involving  the  angle, 
the  gingival  and  incisal  point  angles  are  deepened  as  in 
"(2),"  for  the  simpler  cases.  In  the  incisal  step  form,  the 
entire  step,  which  has  been  given  a  flat  floor,  is  dovetailed 
on  its  labial  and  hngual  waUs,  and  slightly  deepened  at  its 
extremity  (Figs.  153  and  159).  In  the  lingual  step  form 
the  step  is  dovetailed  throughout,  and  its  two  point  angles 
rendered  more  acute  (Fig.  154).  (4)  In  proximo-occlusal 
cavities  on  bicuspids  and  molars  the  gingi\'al  point  angles  are 
rendered  more  acute  in  both  the  simple  mortise  form  and  the 
compound  mortise  form  (Figs.  144,  157  and  158).  The 
simple  mortise  form  is  now  transformed  into  the  dovetail 
mortise  form  by  cutting  at  the  expense  of  the  buccal  and 
lingual  waUs,  rendering  the  cavity  wider,  bucco-linguaUy, 
at  the  junction  of  the  buccal  and  lingual  walls  with  the 
axial  wall  (Fig.  144).  In  the  compoimd  mortise  form, 
after  accentuating  the  gingival  point  angles,  dovetail  the 
lateral  walls  of  the  auxiliary  portion  (the  step),  and  shghtly 
deepen  the  two  point  angles  in  that  portion  (Figs.  145,  146 
and  158). 
Technic  for  Retention  Form. 

Use  the  chisel,  hatchet  and  hoe.  In  deepening  the  gin- 
gival point  angles,  do  so  more  at  the  expense  of  the  axial, 
labial,  buccal  and  lingual  walls,  than  of  the  gingival  wall. 
Place  the  blade  of  the  instrument  in  the  point  angle,  and  after 
slightly  deepening  it  at  the  expense  of  the  gingival  wall,  cut 


112 


PREPARATION    OF    CAVITIES 


along  the  line  angle  uniting  the  labial,  buccal  or  lingual  wall 
(as  the  case  may  be)  with  the  axial  wall,  for  a  distance  of 
about  one-fourth  the  length  of  the  wall,  thus  forming  a  slight 
groove,  which  gradually  disappears  at  its  termination  (Fig. 
162) .  For  making  the  incisal  retention  form  in  proximal  cavi- 
ties in  incisors  and  cuspids,  use  the  acute  angle  hatchet,  placing 
its  blade  in  the  point  angle  and  cutting  at  the  expense  of  the 

labial  and  lingual  walls,  as  well  as 
deepening  the  angle  toward  the  in- 
cisal.   (See  Illustration,  Fig.  151.) 

4.  BEVEL  AND  POLISH  EN- 
AMEL MARGINS.— What  has 
been  said  about  resistance  and  re- 
tention forms  applies  entirely  to 
the  dentin,  these  forms  being  pro- 
vided for  at  the  expense  of  that 
material.  The  enamel  is  an  ex- 
tremely brittle  substance,  owing  to 
its  chemical  composition  (being 
Fig.  i62.-Accentuating  the  gin-    composed  largely  of  inorganic  salts) 

gival  point  angle  for  convenience  and  itS  histological  StrUCturC.  Mi- 
and  retention  form.  •      n        • 

croscopically,  it  consists  of  numer- 
ous layers  of  hexagonal  shaped  rods,  united  together  with  ce- 
menting substance.  Each  individual  rod  is  composed  of  prisms 
placed  end  to  end,  each  of  these  also  united  (much  more  firmly 
than  the  rods)  with  cement  substance.  Mechanically,  the 
material  resembles  a  brick  wall,  the  prisms  representing  the 
individual  bricks  and  the  rods  representing  a  single  layer  of 
them,  the  layers  being  superimposed  one  upon  the  other.  The 
difference,  though,  between  the  enamel  and  the  brick  wall 
is  that  in  the  wall  the  various  layers  run  parallel  to  the  surface 
on  which  they  are  placed,  while  in  the  enamel  they  run  per- 
pendicular to  the  dentin,  radiating  around  in  various  direc- 


CHARACTERISTICS    OF    THE    ENAMEL 


I  13 


tions,  depending  on  the  surface  from  which  they  are  viewed, 
one  Old  of  I  he  rod  lying  on  the  denlifi,  the  otJier  being  at  the 
surface. 

If  the  underlying  dentin  be  first  undermined  by  decay  or 
through  the  action  of  cutting  instruments,  these  rods  may  be 
easily  chipped  away  in  layers  in  the  direction  of  their  length, 
by  means  of  chisels.  Owing  to  the  fact  that  they  run  in  vari- 
ous directions,  depending  on  location,  it  is  necessary  that  a 


Fig.  163. — Diagram  showing  the 
direction  of  the  enamel  rods  on  a 
bicuspid.     Mesial  \-ie\v. 


Fig.  164. — Radiation  of  the  enamel  rods  on 
a  molar.     Mesial  view.     (Diagrammatic.) 


brief  study  of  them  be  here  made,  in  order  that  we  may  intelli- 
gently and  expeditiously  chisel  them  away. 

Rule. — On  plane  surfaces  the  enamel  rods  are  placed 
perpendicular  to  the  dentin;  on  concave  surfaces  they  radiate 
toward  each  other,  while  on  convex  surfaces  they  radiate 
away  from  each  other. 

By  referring  to  the  illustrations  (Figs.  163  and  164),  it 
will  be  seen  (i)  that  their  outer  ends  approach  each  other 
at  pits  and  fissures  in  bicuspids  and  molars:  (2)  that  they 
radiate  more  and  more  to  the  perpendicular,  as  the  points 


114 


PREPARATION    OF    CAVITIES 


of  the  cusps  are  reached;  (3)  then,  as  we  go  over  to  the 
axial  surfaces,  they  begin  to  run  more  and  more  horizont- 
ally to  the  long  axis  of  the  tooth;  and  (4),  as  the  cervical 
line  is  approached,  their  outer  ends  begin  to  radiate  toward 
the  cervical,  following  the  general  law  already  mentioned, 
viz.,  that  they  run  perpendicular  to  the  surface  of  the  dentin. 
Practically  the  same  conditions  exist  in  the  centrals, 
laterals  and  cuspids,  the  same  general  laws  being  applicable 


Fig.  165. — Radiation  of  enamel  rods  on  an 
incisor.     Labial  view.     (Diagrammatic.) 


Fig.  166. — Proximal  view  of  a 
central  incisor  showing  radiation 
of  enamel  rods.    (Diagrammatic.) 


(Figs.  165  and  166).  (i)  On  incisal  surfaces  the  rods  are 
perpendicular  to  the  long  axis  of  the  tooth;  (2)  at  the  angles 
the  rods  on  the  incisal  and  axial  surfaces  approach  each  other; 
(3)  while  on  axial  surfaces  they  He  more  or  less  horizontal  to 
the  long  axis  of  the  tooth;  (4)  radiating  gingivally  as  the 
cervix  is  approached. 

In  the  manipulations  incident  to  the  fourth  step  of  cavity 
preparation,  the  established  law  is  to  bevel  the  enamel  mar- 


BEVELING   ENAMEL    MARGINS  II5 

gins  outward,  following  the  direction  of  the  rods  in  the  loca- 
tion in  which  we  arc  working.  The  dentin  is  the  natural 
support  of  the  enamel.  A  study  of  the  accompanying  illus- 
trations will  demonstrate  why  bevel  of  these  margins  is  nec- 
essary in  order  that  no  rods  be  left  unsupported,  the  amount 
of  bevel  depending  on  the  direction  of  the  rods.  In  pit  and 
fissure  cavities  very  little  bevel  is  necessary,  the  amount  being 
increased  with  the  increase  in  size  of  the  cavity,  and  the 
approach  of  its  margins  toward  the  points  of  the  cusps.  In 
proximal  cavities  a  marked  bevel  is  indicated  at  the  gingival 
margin  (see  illustration),  while  the  amount  on  the  incisal 
margins  will  depend  on  their  proximity  to  the  angle  and  the 
convexity  of  the  surface,  the  rods  deviating  more  at  the  angles 
and  on  distal  convex  surfaces. 

In  centigrades  the  amount  of  bevel  for  cavity  margins  will 
usually  range  between  2  and  7  degrees,  depending  on  location 
and  the  filling  material  to  be  used.     The  tendency  of  beginners 
will  be  to  bevel  too  much. 
Technic  for  Beveling  and  Polishing  Enamel  Margins. 

Chisels  of  razor-like  sharpness  are  the  instruments  indi- 
cated in  the  majority  of  cases.  The  bevel  should  always  be  a 
definite  one,  and  on  straight  lines,  not  curved.  If  the  chisel  is 
of  proper  sharpness,  the  margins  may  be  sufficiently  smoothed 
and  polished.  When  two  margins  join  each  other  at  an  angle, 
the  angle  should  be  slightly  rounded,  being  careful  to  leave  the 
definite  line  angle  in  the  underlying  dentin.  For  gingival 
margins.  Black's  gingival  trimmers  are  constructed  so  as  to 
give  the  proper  bevel.  These  may  also  be  used  on  buccal, 
labial  and  lingual  margins,  or  else  the  Black  enamel  hatchets. 

Technic. — Bevel  with  chisels  the  margins  of  the  cavities  in 
the  plaster  cubes  illustrating  the  various  mortise  forms;  also 
those  prepared  in  the  plaster  and  extracted  teeth,  as  well  as 
on  the  technic  block. 


ii6 


PREPARATION   OP    CAVITIES 


5.  PERFORM  THE  TOILET  OF  THE  CAVITY.— Re- 
move all  debris,  smooth  the  walls,  cleanse  and  dry  thoroughly 
with  cotton,  inspect  for  and  remove  any  remaining  decay, 
after  which  the  cavity  is  ready  for  filling. 


Fig.  167. — Bone  handle. 

Technical  Exercises 

I.  Preparing  Cavities  in  the  Bone  Handle.— This  handle 
may  be  obtained  from  the  Wenker  Dental  Mfg.  Co.,  or  the 
S.  S.  White  Dental  Mfg.  Co.    (Figs.  167,  168). 


Fig.  168. — Bone  handle. 


Prepare  with  hatchets,  hoes  and  chisels  the  six  cavities 
indicated  in  the  illustration;  numbers  i,  2  and  3  on  the  broad 


Fig.  169. — Celluloid  handle  or  block  for  cavity  preparation  exercises. 

side  of  the  handle  and  number  5  on  the  narrow  side,  repre- 
senting the  ordinary  form  of  pit  and  fissure  and  gingival  third 


TECHNICAL   EXERCISES   IN   CAVITY   PREPARATION  II 7 


Fig.  170. — Plaster  technic  model  for  cavity  preparation. 


Fig.  171. — Plaster  technic  model  for  cavity  preparation. 


Il8  PREPARATION    OP    CAVITIES 

cavities;  number  6,  a  proximal  cavity  on  an  incisor;  number 
4  on  the  flat  end,  being  similar  in  shape  to  the  step  form  in 
molars. 

2.  Preparing  cavities  in  the  enlarged  plaster  teeth,  carved 
in  the  Dental  Anatomy  Technic  Course. 

Prepare  several  typical  form  pit  and  fissure  and  smooth 
surface  cavities.  The  cuttings  are  to  be  made  with  vulcanite 
chisels  and  scrapers,  after  drawing  the  outline  form  with 
pencil.  Deepen  the  convenience  angles  with  hatchet  and  hoe 
excavators  and  chisels. 

In  case  no  enlarged  plaster  teeth  are  carved  in  the  Dental 
Anatomy  Course,  excellent  preliminary  cavity  preparation 
work  may  be  done  on  the  models  here  illustrated,  Figs. 
170  and  171,  which  the  author  has  found  very  valuable  in 
his  own  classes.  The  teeth  were  first  carved  in  modelling 
composition  from  Black's  average  measurements,  enlarged 
five  times.  From  these,  sectional  plaster  molds  were  made, 
which  were  then  duplicated  in  Babbit's  metal,  from  which  the 
plaster  teeth  were  obtained.  The  bases  in  which  the  teeth 
are  mounted  were  made  in  the  same  manner.  The  teeth 
are  removable. 

3.  Preparing  cavities  in  the  ivory  teeth  carved  in  the 
Dental  Anatomy  Technic  Course.  Typical  cavity  forms  are 
made  with  the  chisels,  hatchets  and  hoes. 

4.  Preparing  Cavities  in  Extracted  Teeth.  ^ — First,  soak  the 
teeth  in  glycerin  one  part  and  water  two  parts,  to  render  them 
less  brittle.     Select  teeth  with  cavities  of  decay  and  prepare 

^  Splitting  Natural  Teeth. — The  exercises  in  the  filing  and  sawing  of  sections 
performed  in  the  Dental  Anatomy  technic  course  have  impressed  upon  the  student's 
mind  the  thickness  of  the  enamel  and  dentin  in  different  locations,  as  well  as  the 
degree  of  proximity  of  the  pulp  chamber  to  the  surface  when  approached  from 
various  directions.  To  still  further  aid  him  in  gaining  a  proper  idea  as  to  the 
depth  of  his  cavity  walls  in  relation  to  the  pulp  and  to  the  surface,  natural  teeth 
may  be  split  in  various  directions  and  these  points  more  thoroughly  studied,  as 
suggested  by  Dr.  A.  E.  Webster. 


TECHNICAL   EXERCISES   IN    CAVITY    PREPARATION  II9 

typical  cavities,  with  the  same  instruments  as  indicated  above. 
Avoid  exposure  of  the  pulp,  and,  in  chiselling  enamel,  cut  in 
the  direction  of  the  rods,  finally  bevelling  in  the  various 
locations  to  avoid  leaving  any  unsupported  rods. 

5.  Preparing  Cavities  in  the  Typodont  or  Odontotype. — 
Practise  the  proper  rests  and  guards. 


CHAPTER  IV 

FILLING  MATERIALS 

Filling. — A  material  so  placed  in  the  prepared  cavity  of  a 
tooth  that  the  physiological  and  mechanical  functions  of  the 
organ,  its  anatomical  form,  occlusion,  contact  point  and 
esthetic  appearance  are  properly  restored  or  preserved,  and 
the  cavity  itself  protected  as  far  as  possible  from  future 
decay. 
Attributes  of  an  Ideal  Filling  Material. 

1.  Insolubility, 

2.  Harmonious  color, 

3.  Adaptability  to  cavity  walls, 

4.  Crushing  resistance, 

5.  Freedom  from  molecular  change, 

6.  Non-conductivity, 

7.  Capability  of  polish, 

8.  Convenience  of  manipulation. 

1.  Insolubility. — The  mouth  frequently  contains,  in  addi- 
tion to  the  watery  constituents  of  the  saliva,  chemical  sub- 
stances, such  as  acids,  which  have  a  tendency  to  unite  with 
and  dissolve  certain  metals  or  their  salts,  as  well  as  tooth 
structure;-  hence  the  necessity  for  the  selection  of  a  filling 
material  which  will  resist  the  action,  not  only  of  water,  but 
also  of  these  chemicals. 

2.  Harmonious  Color.— People  of  refinement  and  culture 
demand  the  use  of  a  filling  material  which,  where  exposed 
to  view,  is  harmonious  in  color,  or  at  least  presents  a  pleasing 
contrast  to  natural  tooth  structure,  being  as  slightly  con- 

120 


THE    IDKAL    FILLING   MATERIAL  121 

spicuous  as  i)ossiblc.  Those  individuals  who  do  not  i)ossess 
this  attribute  of  correct  appreciation  of  the  esthetic  should  be 
educated  in  that  direction  by  a  high  sense  of  the  artistic 
displa\'cd  on  the  jxirt  of  the  ethical  dentist. 

3.  Adaptability  to  Cavity  Walls. — For  filling  teeth,  mate- 
rials should  be  selected  which  can  be  most  perfectly  adapted 
to  the  walls  of  the  cavity  and  maintain  that  adaptation,  in 
order  that  the  cavity  may  be  perfectly  and  permanently 
sealed  against  the  entrance  of  moisture. 

4.  Crushing  Resistance. — During  the  act  of  mastication, 
the  teeth  are  subjected  to  a  crushing  stress  ranging  from  75  to 
250  pounds'  pressure,  depending  on  the  object  incised  or 
chewed,  the  teeth  performing  the  work  and  the  strength  of 
the  muscles  of  mastication.  This  being  the  case,  the  filling 
must  possess  the  necessary  resistance  to  strain  and  wear  as  well 
as  density,  hardness,  and  tenacity,  to  withstand  this  stress. 
The  greater  amount  of  the  latter  qualities  it  contains,  the 
more  ^^ edge  strength^'  it  possesses  when  built  out  over  long 
enamel  bevels. 

5.  Freedom  from  Molecular  Change. — All  matter  is  com- 
])osed  of  atoms  united  together  in  definite  proportions  to  form 
molecules.  These  molecules  possess  certain  characteristics, 
and  have  certain  definite  relationships  to  each  other,  as  far  as 
their  shape,  size,  closeness  of  adaptation  and  position  is  con- 
cerned. In  some  metals,  the  molecules  of  which  they  are 
composed  have  a  much  greater  tendency  to  change  their 
relationship  than  others  under  certain  physical  conditions, 
such  as  constant  pressure,  age,  heat  and  cold.  Filling  mate- 
rials, under  the  conditions  to  which  they  are  subjected  in  the 
mouth,  should  be  especially  free  from  this  tendency  to  molec- 
ular change. 

6.  Non-conductivity. — The  dentinal  fibrilla?,  when  their 
ends  are  exposed,  through  loss  of  the  enamel  covering,  conduct 


122  FILLING   MATERIALS 

to  an  exalted  degree  sensations  of  heat,  cold  and  electricity 
when  present  in  the  mouth,  to  the  pulp.  The  pulp  rebels  on 
reception  of  these  sensations,  responding  in  the  form  of  a 
paroxysm  of  pain.  This  being  the  case,  the  ideal  filling 
material  should  be  a  non-conductor,  so  that  when  placed, 
these  sensations  may  not  be  transmitted  through  its 
substance. 

7.  Capability  of  Polish. — The  highly  polished  condition  of 
the  enamel  prevents,  to  quite  an  extent,  the  accumulation  of 
food  on  its  surface.  Filling  materials  should  be  capable  of 
taking  a  high  degree  of  polish  for  the  same  reason. 

8.  Convenience  of  Manipulation. — Filling  materials  should 
be  easily  and  conveniently  manipulated,  so  that  the  operation 
may  be  completed  quickly,  and  with  as  little  strain  as  possible 
on  patient  and  operator. 

Classification  of  Filling  Materials 

The  materials  to  be  considered  are  Gold,  Amalgam,  Ce- 
ment, Tin,  Gutta-percha.  None  of  these  fill  all  of  the  above 
requirements,  hence  the  ideal  filling  material  has  not  yet  been 
discovered.  Gold,  Amalgam  and  Tin  may  be  considered  as 
Permanent  filling  materials,  as  they  have  sufficient  lasting 
qualities  to  be  classed  in  that  category,  while  Cement  and 
Gutta-percha,  owing  to  their  short  period  of  usefulness,  are 
classed  as  Temporary  filling  materials.  Another  classification 
of  filling  materials  is  into  Plastic  and  Non-plastic.  The 
Plastics  include  Amalgam,  Cement  (zinc  plastics)  and  Gutta- 
percha, these  materials  being  worked  while  in  a  soft  or  plastic 
state,  and  hardening  after  being  placed  in  position;  the  Non- 
Plastics  including  Gold  and  Tin,  which  do  not  possess  this 
quality. 


GUTTA-PERCHA   AS   A   FILLING  MATERIAL  1 23 

PLASTIC  FILLING  MATERIALS 

Gutta-Percha — Cement — Amalgam 

GUTTA-PERCHA 

Origin. — The  purified  concrete  juice  obtained  by  tapping 
the  Isonandra  Gutta,  an  evergreen  tree  found  principally  in 
the  ]Malay  Peninsula  and  Archipelago. 

Characteristics. — Color,  almost  white,  or  rose,  or  grajdsh 
white.  Inodorous.  Slightly  elastic.  It  contracts  on  harden- 
ing or  cooling.  It  is  very  bland  and  unirritating  to  the  soft 
tissues,  and  is  an  absolute  non-conduct ar.  It  in  time  becomes 
porous  and  disintegrates  in  unclean  mouths.  Freely  soluble 
in  chloroform,  while  oil  of  eucal>ptus,  eucalyptol  and  oil  of 
cajeput  have  a  softening  effect  on  it.  Heat  softens  it,  but  it 
hardens  again  on  cooling. 

Varieties  of  Dental  Gutta-percha. — Gutta-percha  is  not 
used  in  dentistry  in  its  pure  state,  but  is  combined  with  other 
materials  to  give  it  desirable  working  qualities.  Of  these, 
the  principal  ones  are  white  wax,  zinc  oxid,  or  calcium  oxid. 
Gutta-percha  for  dental  use  may  be  classified  under  one  of 
the  following  headings: 

1.  Low  heat — softens  below  200°  F.     (i  part  Gutta- 
percha, 4  parts  Zinc  Oxid). 

2.  Medium  heat — softens  from  200°  to  212°  F.     (i 
part  Gutta-percha,  6  or  7  parts  Zinc  Oxid). 

3.  High  heat — softens  from  210°  to  225°  F.     (Zinc 
Oxid  to  saturation). 

There  are  a  number  of  varieties  of  Gutta-percha  in  use 
for  dental  purposes,  among  which  are  the  following : 

1.  Excelsior  Gutta-percha— high  heat— (softens  at  225°F.). 

2.  Premium  Gutta-percha — medium  heat — (softens  at 
208°  F.). 


Formula : 
(Herman  Prinz) 


124  FILLING   MATERIALS 

3.  Superior  Gutta-percha  Stopping — high  heat. 

'  Medium  Heat, 

4.  Flagg's  Gutta-percha  Stopping     High  Heat, 

Low  Heat. 

5.  White  Base  Plate  Gutta-percha — medium  heat. 

6.  Pink  Base  Plate  Gutta-percha — medium  heat. 

7.  Hill's  Stopping. 
Feldspar  i  part, 
Quartz  i  part, 
Quicklime  2  parts. 
Gutta-percha  base  plate  q.s.  to    make 

a  stiff  paste. 

8.  Temporary  Stopping — (dressing  seal) — low  heat. 
[  White  or  Pink  Base  Plate  4  parts, 

Formula :       ]  Zinc  Oxid  4  parts, 
I  White  Wax  i  part. 
Used  for  sealing  temporary  dressings. 

9.  Gutta-percha  Points  for  Filling  Canals. 
Advantages  of  Gutta-percha. 

1.  Non-conductivity. 

2.  Ease  of  introduction. 

3.  Harmonious  color  (the  white  varieties). 

4.  Elasticity — (an  advantage  in  making  slow  separa- 
tion) . 

Disadvantages. 

1.  Low  Crushing  resistance.  It  cannot  be  used  as  a 
permanent  filling  material  on  surfaces  exposed  to 
mastication. 

2.  Subject  to  chemical  action  of  lactic  acid  and  sulfids 
in  unclean  mouths,  readily  disintegrating. 

3.  Shrinkage  on  cooling,  with  consequent  tendency  to 
draw  from  cavity  walls. 

4.  Incapability  of  polish. 


MANIPULATION    OF    GUTTA-PERCHA  1 25 

Uses. 

1.  As  a  temporary  filling  material  in  deciduous  teeth. 

2.  As  a  more  or  less  temporary  filling  material  in  un- 
exposed cavities  in  permanent  teeth. 

3.  For  sealing  in  dressings. 

4.  For  producing  slow  separation. 

5.  For  fdling  root  canals. 

6.  For  temporarily  setting  crowns  and  bridges. 

7.  As  a  cavity  lining  and  for  filling  small  canals  in  the 
form  of  chloro-percha. 

Chloro-percha  is  made  by  dissolving  shavings  of  base 
plate  gutta-percha  in  chloroform.  On  the  evaporation  of  the 
chloroform  the  gutta-percha  is  left  on  the  cavity  wall  or  in  the 
canal. 

Method  of  Manipulation.^ — Give  the  cavity  retenti^'e  form. 
Before  insertion,  the  walls  may  be  slightly  moistened  with 
eucal>^tol,  oil  of  eucal}^tus,  or  oil  of  cajuput,  preferably  the 
first  agent  mentioned.  Avoid  overheating  the  gutta-percha, 
as  the  product  is  thus  easily  injured.  Heating  may  be  accom- 
plished over  the  alcohol  lamp,  Bunsen  burner,  Flagg's  Gutta- 
percha heater  (Figs.  172  and  173),  the  thermoscopic  heater, 
or  on  an  electric  annealer;  then  follow  one  of  the  following 
methods. 

I.  Cut  the  Gutta-percha  into  small  pieces,  soften  with  heat 
and  pack  each  piece  separately,  condensing  thoroughly  with 
cold  burnishers  of  suitable  size.  Avoid  much  excess,  as  the 
material  is  rather  difficult  to  remove.  Remove  surplus 
material  immediately  with  a  hot  flat  spatula,  trimming  toward 
the  margins.  Smooth  the  surface  of  the  filling  with  the  same 
instrument,  slightly  warmed.  If  preferred,  the  fiUing  may  be 
allowed  to  cool  and  harden  thoroughly,  when  the  excess  is  re- 
moved with  a  sharp  knife  blade,  but  the  knife  must  be  \ery 
keen  to  avoid  drawing  the  fiUing  away  from  the  margins. 


126 


FILLING   MATERIALS 


Fig.  172. — Flagg's  gutta-percha  and  tool  heater. 


Fig.  173. — Thermoscopic  heater  for  gutta-percha. 


CLASSIFICATION    OF    CEMENTS  T27 

2.  In  cavities  of  easy  access,  heat  the  Gutta-percha  and, 
while  soft,  mold  into  a  mass  of  sufficient  size  to  fill  the  cavity, 
packing  with  a  warm  burnisher,  condensing  thoroughly  against 
the  walls,  and  trimming  the  excess  after  either  of  the  above 
methods.  Then  go  over  the  surface  of  the  filling  with  a  pledget 
of  cotton  or  spunk,  moistened  with  chloroform.  For  illustra- 
tions of  burnishers  see  Figs.  94  and  95. 
Technical  Exercises. 

Fill  several  of  the  cavities,  prepared  during  the  study  of 
cavity  preparation,  using  both  methods  as  outlined  above. 

CEMENT 

There  are  four  varieties  of  cements  used  in  dentistry,  each 
receiving  a  name  depending  on  its  chemical  composition. 
Cements  consist  of  a  powder  and  a  liquid,  which  when  mixed 
together,  form  a  more  or  less  hard  mass.  The  composition  of 
these  is  largely  a  trade  secret,  but  for  all  practical  purposes  it 
is  as  follows: 

Classification  of  Cements 

I.  Oxyphosphate  of  Zinc  /  Powder,  Zinc  Oxid  (calcined) 

(Basic  Zinc  Phosphates)  i  Liquid,  Phosphoric  Acid 

j  Powder,  Cupric  Oxid 


2.  Oxyphosphate  of  Copper 

3.  Oxychlorid  of  Zinc 


\  Liquid,  Phosphoric  Acid 
j  Powder,  Zinc  Oxid  (calcined) 
]  Liquid,  Zinc  Chlorid  (deliquesced) 
'  Beryllium, 


4.  Silicates. 


-.       ,       ,   Silicia, 
Powder  <    , , 

Aluminum, 


Calcium  Compounds 
Liquid,  Phosphoric  Acid 


Characteristics. — All  of  the  cements  are  intended  for  tem- 
porary filhng  work,  unless  covered  by  some  more  permanent 
material,  as  they  are  more  or  less  soluble  in  the  oral  fluids,  (i) 
The  OxypJiospIiafe  of  Zinc  (basic  zinc  ]^hosphatcs)  is  the  most 


128  FILLING   MATERIALS 

important  of  these  preparations,  and  most  universally  used. 
It  may  be  obtained  in  various  shades  to  harmonize  with  the 
color  of  the  teeth,  and  is  much  more  lasting  than  the  oxy- 
chlorid.  It  is  largely  used  for  temporary  filling  work,  for 
cementing  crowns  and  bridges,  inlays,  orthodontia  appliances, 
and  as  an  intermediate  (between  the  fiUing  and  cavity).  (2) 
The  Oxyphosphate  of  Copper  (color  inky  black)  is  extremely 
sticky,  and  clings  tenaciously  to  dry  cavity  walls.  It  is  also 
antiseptic  (against  infection)  in  character,  and  markedly 
bland  to  sensitive  cavities.  For  this  reason  it  is  used  for 
filling  cavities,  pulp  chambers  and  canals  in  temporary  teeth; 
also  cavities  in  permanent  teeth  whose  sensitiveness  will  not 
permit  of  proper  cavity  preparation.  On  account  of  its  color 
it  has  to  be  confined  to  posterior  teeth.  (3)  The  Oxychlorid 
of  Zinc  is  now  seldom  used  as  a  filling  material,  except  in  root 
canals,  as  it  quickly  disintegrates  in  contact  with  moisture. 
It  is  extremely  irritating  to  vital  tissues,  and  cannot  be  used  in 
close  proximity  to  the  pulp,  but  is  still  utilized  by  some  as  an 
intermediate,  on  account  of  its  antiseptic  properties  and  its 
white  color.  (4)  The  Silicate  Cements,  recently  introduced, 
are  in  a  stage  of  experimentation.  Great  claims  are  made  for 
them  by  their  manufacturers  as  permanent  filling  materials, 
if  properly  handled;  but  there  is  a  great  variation  in  the  results 
so  far  obtained  by  different  operators.  They  are  translucent 
and  more  nearly  harmonize  with  the  color  and  appearance  of 
enamel  than  the  other  cements. 
Advantages  of  Cements. 

1.  Non-conductivity  (except  silicates,  most  of  which 
require  an  intermediate). 

2.  Harmonious  color  (except  oxyphosphate  of  copper, 
which  is  black). 

3.  Adhesiveness  to  cavity  walls  (except  silicates). 

4.  Ease  of  introduction. 


METHOD   OF   MIXING   CEMENTS  129 

Disadvantages. 

1.  Lack  of  edge  strength. 

2.  Low  crushing  resistance. 

3.  Solubility  in  the  fluids  of  the  mouth. 

4.  Incapability  of  polish  (except  silicates). 

5.  Change  of  molecular  form  while  setting  (some  ex- 
pand, some  shrink). 

Method  of  Mixing  Cements. — Use  a  clean  glass  slab  (Fig. 
174),  with  a  heavy,  German  silver,  steel,  or  agate  spatula 
(see  Fig.  96),  preferably  German  silver,  which  is  less  readily 
acted  upon  by  the  liquid.  For  the  silicates,  no  steel  instru- 
ments can  be  used  in  the  mixing  or 
packing,  on  account  of  chemical  ac- 
tion, and  consequent  discoloration 
of  the  mass.  Tantalum,  agate, 
ivory,  or  tortoise-shell  instruments 
are  recommended.  The  oxychlorid 
of  zinc  and  oxyphosphate  of  copper 
are  mixed  to  a  creamy  consistence; 
the  oxyphosphate  of  zinc  to  the  con- 

P        ..       r        riT  1    i  f'iG.  174. — Glass  cement  slab. 

sistence  of  putty  tor  nilmg,  and  to  a 

creamy  consistence  for  setting  crowns,  inlays  and  regulating 
appliances.  The  silicates  are  mixed  stiffer  than  the  oxyphos- 
phate of  zinc,  working  in  all  the  powder  possible,  which  will 
be  greater  in  amount  than  that  taken  by  the  liquid  of  the 
zinc  phosphate  cements. 

Directions. — (i)  Place,  by  means  of  a  glass  rod  or  pipette, 
the  necessary  amount  of  liquid  in  the  center  of  the  clean  slab. 
(2)  Deposit,  by  tapping  the  bottle,  or  with  a  clean  spatula  or 
other  convenient  carrier,  the  necessary  amount  of  powder  at 
one  end  of  the  slab.  (3)  Draw  in  one-fourth  of  the  powder 
and  spatulate  thoroughly  with  a  swinging,  circular  movement. 
(4)  Then  draw  in  another  one-fourth  of  the  powder  and  spatu- 
9 


130  FILLING   MATERIALS 

late  as  before  until  thoroughly  mixed,  continuing  to  add  the 
powder,  and  spatulating  until  the  mix  is  of  the  desired  con- 
sistency. (5)  For  fillings,  the  mixing  should  be  continued 
until  the  cement  materially  resists  spatulation,  when  it  is 
scraped  from  the  slab,  and  in  some  instances  rolled  into  a  ball 
ready  for  use.  Directions  accompanying  the  package  specify 
minute  details  of  mixing  silicates  and  other  cements,  these 
varying  to  some  extent,  depending  on  chemical  composition. 

Method  of  Packing. — The  cavity  should  be  dry,  with 
slightly  retentive  form  and  bevel  not  marked.  Pack  in  small 
pieces,  thoroughly  condensing  with  as  much  force  as  the  ma- 
terial will  allow,  by  means  of  smooth  burnishers,  leaving  an 
excess  for  polishing.  As  soon  as  the  material  is  molded  to 
form,  allow  it  to  set  thoroughly  before  removing  the  excess 
and  polishing.  Trim  and  polish  with  knives,  disks  and  strips, 
in  the  case  of  the  silicates  finishing  with  celluloid  strips.  The 
use  of  the  matrix  is  a  necessity  in  complex  cavities,  if  the  best 
results  are  desired. 

Hydraulic  cements  require  the  application  of  water  after 
molding  to  form,  and  before  setting. 

Intermediates 

Sensations  of  heat  and  cold  are  rapidly  transmitted,  by 
means  of  the  dentinal  fibrillae,  to  the  pulp  from  the  walls  of 
cavities,  and  as  the  permanent  filling  materials  are  conductors 
of  these  physical  forces,  it  becomes  necessary  in  all  cavities, 
except  extremely  shallow  ones,  to  place  non-conducting 
substances  between  the  filling  and  the  walls  of  the  cavity. 
These  materials  are  known  as  intermediates,  and  the  act  of 
placing  them  in  position  is  known  as  Pulp  Protection.  The 
substances  most  frequently  used  are  Cement  and  Gutta- 
percha.    Cement  itself   is   a   slight   conductor,   so   that  in 


CIIAKACTERISTICS    OF    AMALGAM  I3I 

extreme  cases  of  hypersensitivity  a  thin  layer  of  (iutta-j)ercha, 
Chloropercha,  or  one  of  the  Cavity  Linings,  is  ai)pHed,  and 
then  covered  with  cement,  when  the  balance  of  the  filling  is 
placed  in  position.  Cavity  Linings  are  colorless,  transparent 
liquids,  which,  on  evaporation,  leave  a  thin,  non-conducting 
film  on  the  walls  of  cavities.  Two  prominent  varieties  of  these 
are  Cavitine  and  Gilbert^ s  Cavity  Lining. 
Technical  Exercises. 

1.  Carefully  mix  a  batch  of  cement,  according  to  the  direc- 
tions given  above,  stirring  in  small  amounts  of  the  powder 
at  a  time,  and  spatulating  thoroughly  to  accomplish  mechanical 
and  chemical  union  of  powder  and  liquid.  Roll  into  a  round 
mass. 

2.  Mix  another  batch  by  adding  the  powder  in  large 
amounts,  and  avoiding  thorough  spatulation.  Roll  into  a 
mass  as  in  No.  i. 

3.  Place  the  two  mixes  in  ink  or  aniline  dye  for  twelve 
hours,  and  then  compare  for  cutting  consistence  as  well  as 
amount  and  penetration  of  the  stain. 

4.  Insert  several  cement  intermediates  in  the  cavities 
already  prepared,  building  some  up  in  step  form. 

5.  Insert  several  cement  fillings,  with  and  without 
matrices. 

AMALGAM 

Definition. — An  alloy  or  union  of  mercury  with  one  or  more 
other  metals.  Most  dental  amalgams  consist  of  a  combination 
of  mercury  with  silver,  tin,  copper  or  zinc.  To  these  are 
also  sometimes  added  gold,  platinum  and  other  metals. 

Alloy. — A  union  of  two  or  more  metals  by  means  of  heat. 
The  metals  are  usually  melted  in  a  closed  electric  crucible 
in  an  atmosphere  of  hydrogen.     After  cooHng  and  hardening, 


132  FILLING  MATERIALS 

the  resultant  mass  is  known  as  an  Ingot.  The  ingot  is  either 
filed  into  small  granules  or  pared  into  fine  shavings,  when, 
after  being  annealed  and  carried  through  certain  other  proc- 
esses it  is  dispensed  as  alloy  for  dental  use. 

Properties  of  Amalgam 

All  dental  alloys,  when  mixed  with  mercury,  possess  one 
or  more  of  the  following  properties,  which  are  imparted  to  the 
mass  by  qualities  inherent  in  the  constituents,  viz., 

1.  Spheroiding. 

2.  Flow. 

3.  Shrinkage. 

4.  Expansion. 

Spheroiding. — The  tendency  to  become  round  imparted  to 
the  mass  by  the  mercury.  It  only  occurs  while  the  amalgam 
is  hardening  or  setting,  and  depends  on  the  amount  of  mercury 
left  in  the  mass,  the  greater  the  excess  of  mercury  present,  the 
more  marked  the  spheroiding. 

Flow. — Many  metals,  when  subjected  to  constant  stress,  as 
from  the  stress  of  mastication,  possess  the  tendency  to  slowly 
move  from  under  the  stress,  thus  gradually  changing  their 
shape.  Some,  notably  tin,  possess  more  of  this  property 
than  others.  [| 

Shrinkage  and  Expansion. — Some  metals,  when  heated 
or  amalgamated  (mixed  with  mercury),  shrink,  while  others 
expand.  The  ideal  amalgam  would  be  one  in  which  the  con- 
stituents are  so  combined  as  to  possess  neither  of  the  above 
qualities,  and  has  not  as  yet  been  discovered. 

Amalgams  possess,  in  addition  to  the  above  qualities, 
certain  advantages  and  disadvantages. 
Advantages. 

1.  Crushing  resistance. 

2.  Insolubility. 


CHARACTERISTICS   OF   AMALGAM  1 33 

3.  Convenience  of  manipulation. 

4.  Capability  of  polish. 
Disadvantages. 

1 .  Inharmonious  color. 

2.  Tendency  to  molecular  change. 

(a)  Spheroiding. 

(b)  Flow. 

(c)  Expansion. 

(d)  Shrinkage. 

3.  Lack  of  edge  strength  when  built  to  thin  edges. 

4.  High  conductivity. 

Metallurgical  Properties  of  Silver,  Tin,  Copper  and  Zinc 
The  various  metals  in  dental  alloys  possess  certain  prop- 
erties, some  of  which  they  impart  to  the  mass  when  combined 
with  mercury.  Some  desirable  qualities  of  one  metal  over- 
come certain  undesirable  ones  of  another  in  the  combination, 
if  the  metals  are  combined  in  the  correct  proportions. 
Silver. 

1.  Unites  with  mercury  fairly  readily  in  definite  atomic 
proportions. 

2.  Tarnishes. 

3.  Expands. 

4.  Retards  setting. 

5.  Increases  edge  strength. 

6.  Lessens  flow. 

7.  Works  hard. 


Tin. 


1 .  Unites  readily  with  mercury  in  all  proportions. 

2.  Retards  setting. 

3.  Increases  flow. 

4.  Imparts  plasticity. 

5.  Shrinks. 

6.  Decreases  edge  strength. 


134  FILLING   MATERIALS 

Copper. 

1.  Unites  with  mercury  with  difficulty  in  definite  atomic 
proportions. 

2.  Hastens  setting. 

3.  Increases  edge  strength. 

4.  Lessens  flow. 

5.  No  appreciable  expansion  or  contraction. 

6.  Tarnishes  readily. 
Zinc. 

1.  Unites  easily  with  mercury  in  definite  atomic  propor- 
tions. 

2.  Expands. 

3.  Hastens  setting. 

4.  Diminishes  edge  strength. 

5.  Increases  flow. 

6.  Improves  color. 

7.  Imparts  plasticity. 

Classification  of  Amalgams 

Amalgams  may  be  classified  according  to  the  number  of 
constituents  they  contain  into : 

1.  Binary — one  containing  mercury  and  one  other  metal. 
Example,  copper  amalgam. 

2.  Ternary — one  containing  mercury  and  two  other 
metals.  Example,  Townsend's  amalgam,  containing  mer- 
cury, silver  and  tin. 

3.  Quaternary — one  containing  mercury  and  three  other 
metals  (Black's  amalgams).  Example,  mercury,  silver,  tin 
and  copper. 

4.  Quinary — one  containing  mercury  and  four  other 
metals.  Example,  mercury,  silver,  tin,  copper  and  zinc. 
Most  of  the  amalgams  in  use  today  are  either  Quaternary  or 
Quinary  amalgams. 


CHARACTERISTICS    OF    AMALGAM  I35 

Classification  of  Alloys 

Allo}'s  may  be  classified  into  two  divisions,  as  follows: 

1.  High-percentage,  or  Quick-setting  Alloys  (containing 
a  high  percentage  of  silver). 

Formula:  Silver 65  to  68      per  cent 

Tin 26  to  28      per  cent. 

Copper 3  to    4 . 5  per  cent. 

Zinc I  to    2.5  per  cent. 

Properties. — (i)  Quick  setting.  (2)  Hard  working  (lack 
of  plasticity).  (3)  Great  crushing  resistance  and  edge 
strength.  (4)  Stability  of  form  (minimum  of  shrinkage, 
expansion  and  flow) .  These  alloys  are  sometimes  designated 
Dr.  Black's  alloys,  but  they  are  wrongly  named,  as  they  do 
not  follow  his  formulae. 

2.  Low-percentage,  Slow-setting  or  Plastic  Alloys. 

Formula:  Silver 43  to  48  per  cent. 

Tin 48  to  58  per  cent. 

Zinc I  to    2  per  cent. 

Properties. — (i)  Slow  setting.  (2)  Lighter  in  color.  (3) 
Plasticity  (easy  working).  (4)  Less  crushing  resistance  and 
edge  strength.  (5)  Greater  shrinkage,  expansion  and  flow. 
(6)  Require  less  mercury  to  amalgamate. 

Amalgam,  on  account  of  its  inharmonious  color,  should  be 
confined  to  the  posterior  teeth. 

Method  of  Mixing. — The  proportion  of  mercury  to  the 
alloy  varies  in  diiferent  formulae  and  is  obtained  by  testing 
the  batch,  or  from  printed  directions  on  the  package.  The 
average  is  about  five  parts  of  alloy  to  seven  parts  of  mercury 
by  weight.  Rapid-setting  alloys  usually  require  more  mer- 
cury. To  prevent  change  of  form  and  to  give  the  greatest 
edge  strength,  all  excess  of  mercury  must  be  removed  in  mixing. 

Directions. — (i)  Place  the  desired  amount  of  alloy  in  a 
wedgewood  or  glass  mortar,  preferably  the  latter,  and  add  the 


136 


FILLING   MATERIALS 


necessary  amount  of  mercury  by  weight.  (2)  Mix  thoroughly 
with  the  pestle  (Fig.  175)  until  the  alloy  and  mercury  are  com- 
pletely incorporated.  (3)  Remove  to  the  dry  and  clean  palm 
of  the  left  hand  and  work  vigorously,  rapidly  and  continuously 
with  the  fingers  of  the  right  hand  for  from  three  to  five  min- 
utes, squeezing  frequently  and  removing  excessive  mercury 
until  a  characteristic  cry  of  the  mass  is  heard  when  in  close 
proximity  to  the  ear.  (4)  With  the  thumb  and  forefinger, 
forcibly  squeeze  out  all  remaining  excess  of  mercury;   or 


Fig.  175. — Glass  mortar  and  pestle. 

transfer  it  to  a  piece  of  cloth  or  chamois  and  wring  with  a 
pair  of  pliers.     Pack  immediately. 

Method  of  Packing. — Cut  the  mass  into  several  small 
pieces  (depending  on  the  size  of  the  cavity)  with  a  flat  bur- 
nisher. Do  not  use  too  large  pieces.  Pack  with  serrated 
amalgam  pluggers,  Black's  or  Ivory's  (Figs.  91  and  92).  Do 
not  use  smooth  burnishers.  Pack  with  steady,  forcible  hand 
pressure,  condensing  thoroughly  one  piece  at  a  time.  Pack 
toward  the  walls,  wedging  the  several  pieces  between  each 
other  and  the  walls.  If  any  excess  of  mercury  appears  on  the 
surface  during  the  packing  and  wedging  process,  remove  it 


CHARACTERISTICS   OF   AMALGAM  I37 

with  spoon  or  discoid  excavators  before  continuing.  Do  not 
use  tin  foil  or  gold  foil  for  this  purpose  on  account  of  the 
danger  of  forming  a  new  alloy,  possessing  new  properties. 
Pack  the  cavity  overfull,  and  allow  the  mass  to  set  for  several 
minutes  before  removing  the  excess.  Trim  the  excess  with 
flat  burnishers  and  knives  toward  the  margins,  leaving  the 
hlling  carved  to  full  contour  on  proximal  surfaces,  and  to 
proper  form  on  others.  The  final  polishing  is  deferred  for 
twenty-four,  or  better  forty-eight  hours,  to  allow  for  com- 
plete setting.     Directions  for  polishing  are  given  on  page  159. 

Cavity  Preparation  for  Amalgam  Work  varies  very  little 
from  that  for  gold.  The  various  steps  as  described  in  the 
chapter  on  cavity  preparation  should  be  carefully  and  con- 
scientiously completed.  Convenience  angles  are  not  necessary 
for  starting  the  filling,  the  usual  retention  and  resistance  form 
being  all  that  is  necessary.  Owing  to  its  lack  of  edge  strength, 
the  amount  of  bevel  of  the  cavo-surface  angle  should  be 
modified  as  much  as  conditions  will  allow. 

Matrices. — For  filling  with  amalgam,  the  presence  of  four 
lateral  walls  to  the  cavity  is  a  necessity,  to  prevent  the  squeez- 
ing out  of  the  mass  during  the  application  of  the  great  force 
required  during  the  packing  process.  In  cavities  lacking 
four  walls,  the  missing  wall  is  supplied  by  the  use  of  a  thin 
metal  band  of  steel  or  German  silver  in  the  form  of  a  matrix. 
For  technic  purposes  in  the  laboratory,  a  thin  band  of  German 
silver,  2/3  or  3/4  the  circumference  of  the  tooth,  may  be  tied 
in  position  by  means  of  floss  silk,  or  binding  wire,  encircling 
the  tooth  several  times.  If  the  exercises  in  filling  are  per- 
formed on  natural  teeth,  with  extensive  cavities,  a  measure- 
ment of  the  neck  of  the  tooth  may  be  taken,  and  a  soldered 
band  made  to  completely  encircle  the  tooth. 

Technical  Exercises. — Fill  the  cavities  in  the  posterior 
teeth  prepared  during  the  studies  in  cavity  preparation. 


138  FILLING  MATERIALS 

NON-PLASTIC  FILLING  MATERIALS 

Tin— Gold 

TIN 

Characteristics. — Tin,  when  pure  and  freshly  cut,  is  co- 
hesive (the  separate  particles  clinging  to  each  other) ,  like  gold. 
It  rapidly  loses  this  property,  though,  on  exposure  to  the 
atmosphere,  and  gradually  becomes  non-cohesive.  Until 
recently  it  was  worked  almost  exclusively  after  the  non- 
cohesive  method.  There  have  recently  been  introduced  sev- 
eral preparations  of  tin  which  are  very  cohesive,  one  of  which 
is  known  as  Duplex,  a  cohesive  tin  covered  with  cohesive 
gold.  Another,  which  receives  the  trade  name  of  Crystallia, 
is  prepared  in  coarse  silver- colored  shreds. 

Tin  is  very  little  used  as  a  filling  material  today.  It  may 
be  utilized  in  the  technic  laboratory  for  experimental  purposes, 
as  a  substitute  for  gold.  For  working  on  the  cohesive  princi- 
ple, it  may  be  prepared  for  use  after  the  following  method. 
Take  a  corundum  wheel,  i  3/4  to  2  1/2  inches  in  diameter, 
and  make  a  mold  in  sand  or  marble  dust.  After  removing 
the  wheel,  pour  melted  pure  tin  into  the  impression  in  the 
sand  or  marble  dust,  thus  duplicating  the  wheel  in  tin.  Mount 
on  a  mandrel  on  the  laboratory  lathe,  and,  while  revolving 
rapidly,  cut  fine  shavings  with  a  sharp  carpenter's  chisel. 
These  shavings,  if  worked  while  freshly  cut,  will  be  very 
cohesive. 

Tin  is  placed  on  the  market  in  sheets  4  inches  square, 
the  same  sizes  and  numbers  as  gold  foil,  ranging  numbers  2, 
3,  4,  5,  6,  8,  10,  20,  30,  40,  60  and  120.  It  is  prepared  by  the 
manufacturer  in  the  same  manner  as  gold,  by  rolling  an  ingot 
into  strips  and  then  rolling  thinner  for  the  higher  numbers, 
and  beating  by  machinery  for  the  lower  numbers.     The  num- 


CHARACTERISTICS    OF   TIN  I39 

ber  indicates  the  number  of  grains  to  the  sheet,  viz.,  a  sheet  of 
No.  4  foil  weighs  4  grains.  No.  10  weighs  10  grains,  etc. 

Tin  foil,  as  well  as  gold  foil  (cohesive  or  non-cohesive) 
is  prepared  for  use  in  various  forms  by  the  operator  or  his 
assistant. 
The  principal  forms  used  are : 

1.  The  Roll. 

2.  The  Ribbon  or  Tape. 

3.  The  Rope. 

4.  The  Cylinder. 

5.  The  Mat  or  Cushion. 

Method  of  Preparing.     (Either  tin  or  gold.) 

1.  The  Roll. — (a)  Cut  a  sheet  of  foil  into  quarters,  thirds 
or  halves,  and  place  a  section  near  one  end  of  a  smooth  towel, 
which  has  been  folded  lengthwise,  (b)  Pull  the  other  end  of 
the  towel  over  the  foil,  and  then,  bringing  it  in  contact  with  it, 
quickly  push  the  towel  from  you  in  such  a  manner  as  to  roll 
the  foil  into  a  loose  roll,  (c)  Repeat  the  process  until  the  roll 
is  as  small  as  desired  (Figs.  176  and  177). 

2.  The  Ribbon. — (a)  Cut  the  foil  into  halves,  thirds  or 
quarters,  as  before,  and  lay  a  section  on  a  folded  towel  or 
napkin,  chamois  or  spunk,  held  in  the  left  hand,  (b)  With  a 
large,  clean,  plaster  spatula,  or  preferably  a  gold  folder,  fold 
the  foil  lengthwise  by  placing  the  folder  in  the  center  of  the 
section,  and  bringing  together  the  folds  of  the  towel,  or  other 
article  used,  by  closing  the  hand,  (c)  Repeat  the  operation, 
continuing  to  fold  smaller  and  smaller,  until  the  ribbon  is  the 
desired  width  (Fig.  178). 

3.  The  Rope. — (a)  Twist  a  quarter,  third  or  half  sheet  of 
foil  into  a  rope  between  the  clean  and  dr\' thumb  and  fingers  of 
both  hands,  being  careful  to  make  the  roi)e  as  near  an  equal 
size  throughout  its  length  as  possible.     The  fingers  may  be 


140 


FILLING  MATERIALS 


Fig.  176. — Making  the  roll. 


Fig.  177. — The  roll  completed. 


PREPARING  GOLD  AND  TIN  FOR  USE 


141 


covered  with  finger  cots,  if  the  hands  are  moist.     This  method 
is  hardly  ai)pHcabIe  to  cohesive  gold. 

4.  The  Cylinder. — Roll  a  ribbon  on  a  three-,  four-  or  five- 
sided  smooth  broach  into  a  cyHnder.  The  size  of  the  cyhnder 
will  be  regulated  by  the  length  of  the  ribbon,  and  the  length  of 


/ 


^ 


■/ 


/ 


Fig.  178. — Folding  the  ribbon. 

the  cylinder  by  the  width  of  the  ribbon.  Various  sizes  and 
lengths  are  required,  depending  on  the  size  and  depth  of  the 
cavity.  Gold  cylinders  in  both  cohesive  and  non-cohesive 
forms  are  also  prepared  ready  for  use  by  the  manufacturer 
(Fig.  179). 

5.  The  Cushion  or  Mat. — Fold  a  ribbon  lengthwise  upon 
itself  with  a  spatula,  until  made  into  a  mat  or  cushion.     The 


142 


FILLING  MATERIALS 


size  will  depend  on  the  size  of  the  cavity,  and  may  be  varied 
by  regulating  the  width  of  the  ribbon,  the  amount  of  gold 
used  and  the  number  of  folds. 

Another  Method. — Roll  a  cylinder  on  a  flat-sided  broach. 


Fig.  179. — Making  the  cylinder.     The  broach  and  cylinder  are  shown  much 

enlarged. 


and  then,  after  withdrawal  from  the  broach,  flatten  it  more; 
or  roll  the  cyhnder  as  usual  and  flatten  into  a  mat. 
Advantages  of  Tin. 

I.  Non-conductivity.     (Lowest  of  all  the  metals.) 


CHARACTERISTICS    OF    TIN  I43 

2.  Ease    of    introduction.     (Works    rapidly    when    non- 
cohesive.) 

3.  AdaptabiHty  to  cavity  walls. 

4.  Therapeutic  action.     (Supposed  by  some  to  prevent 
decay.) 

5.  Capability  of  polish.     (It  takes  a  high  polish,  but  does 
not  retain  it.) 

Disadvantages. 

1.  Inharmonious  color.     (Oxidizes  and  darkens  readily.) 

2.  Lack  of  crushing  resistance  and  edge  strength. 

3.  Flow. 

4.  Disintegrates  in  the  fluids  of  the  mouth. 

Tin  is  still  used  by  some  operators  for  filling  cavities  in 
children's  teeth  on  account  of  its  ease  of  introduction  and 
supposed  therapeutic  effect;  also  in  rapid  caries  on  surfaces 
unexposed  to  \dew  and  mastication.  It  is  too  soft  to  be 
subjected  to  the  forces  of  occlusion  in  permanent  teeth.  As 
the  method  of  working  non-cohesive  gold  and  tin  is  identical, 
the  description  here  given  will  apply  to  both  materials. 

Method  of  Working  Tin  or  Non-cohesive  Gold. — The 
cavity  preparation  is  practically  the  same  as  for  cohesive 
gold,  except  that  deepening  of  the  convenience  angles  i.'^ 
omitted,  and,  owing  to  lack  of  edge  strength  in  the  material, 
enamel  bevels  should  not  be  so  acute.  Simple  ca\dties  with 
four  strong  walls  are  a  necessity.  All  filling  materials  are 
packed  more  or  less  after  a  process  of  wedging,  but  the  wedg- 
ing principle  is  carried  to  its  fullest  extent  with  non-cohesive 
gold  and  tin.  Owing  to  the  fact  that  neither  of  these  possesses 
the  property  of  cohesion,  as  the  other  filling  materials  do, 
they  are  mechanically  wedged  into  the  cavity  with  great 
force,  so  that  each  lamina  or  layer  is  dependent  on  the  other 
to  retain  it  in  place.  The  packing  is  done  with  hand  pressure, 
by   means   of   serrated,   wedge-shaped  pluggers,    the     final 


144 


FILLING  MATERIALS 


condensation  being  accomplished  by  means  of  mallet  force. 
Owing  to  the  strength  of  the  thrust  required  for  working  tin 
and  gold  by  the  non-cohesive  method,  larger  handles  than 


m 


lllll 

iiiiif 


M 


,.i: 


Fig.  i8o. — Plugger  handles. 

those  usually  employed  are  necessary  (Fig.  i8o). 

Two  methods  are  employed,  depending  on  the  size  of  the 
cavity  and  the  individual  preference  of  the  operator. 


METHODS    OF    WORKING    TIN. 


145 


1 .  The  Cylinder  or  Cushion  Method. 

2.  The  Ribbon,  Roll,  or  Rope  Method. 

I.  The  Cylinder  Method. — The  cylinder  method  is  the 
more  rapid  when  the  size  of  the  cavity  will  admit  of  its  adop- 
tion. The  cylinders  should  be  of  such  length  that  one  end  will 
protrude  above  the  orifice  of  the  cavity,  while  the  other  rests 
on  the  floor  or  seat.     (Fig.  i8i). 

(i)  Place  enough  cylinders  against  the  wall  farthest  away 
from  the  operator  to  cover  the  wall.  Condense  thoroughly 
against  the  wall  with  the  plugger. 

(2)  In  large  cavities  place  another  layer  of  cylinders  against 


Fig.  181. — Working  gold  or  tin  cylinders  (nou-cohesive) . 


the  first  layer,  and  condense  in  the  same  direction,  holding  in 
position  with  a  plugger  in  the  left  hand. 

(3)  Repeat  the  procedure  on  the  opposite  wall,  and  then 
on  the  two  intervening  walls,  leaving  the  center  of  the  cavity 
unfilled. 

(4)  Force  one  or  more  cylinders  into  the  central  opening, 
the  number  depending  on  its  size,  ramming  them  in  until  the 
cavity  is  full. 

(s)  Force  an  opening,  by  means  of  the  wedge-shaped 
pluggers,  into  another  part  of  the  filling,  and  pack  in  one  or 
more  smaller  cylinders  here,  repeating  this  process  at  other 


146  FILLING   MATERIALS 

points  until  it  is  impossible,  by  great  force,  to  insert  any 
more  cylinders. 

(6)  Thoroughly  condense  with  foot  pluggers  by  means 
of  mallet  force  and  then  burnish. 

(7)  Trim  to  shape,  grind  to  shape,  or  file  to  shape  and 
burnish  again,  continuing  until  the  filling  is  of  proper  fullness; 
then  polish.  Directions  for  polishing  fillings  are  given  on 
page  159. 

2.  The  Ribbon  Method. — This  method  is  practically  the 
same  as  the  preceding,  except  that  instead  of  the  use  of  cyl- 


FiG.  182. — The  ribbon  method. 

inders,  long  ribbons,  rolls  or  ropes  are  folded  upon  themselves, 
starting  on  the  floor  of  the  cavity,  against  the  lateral  wall 
farthest  away,  and  gradually  condensing  ribbons  against  all 
four  walls,  then  in  the  center,  and  finally  in  any  place  they  can 
be  wedged,  always  carrying  the  ribbon  to  the  floor  of  the  cav- 
ity, and  extending  it  well  above  the  margins  to  allow  enough 
excess  for  finishing  (Fig.  182), 

Technical  Exercises 

I.  Prepare  rolls,  ropes,  ribbons,  cylinders  and  mats  or 
cushions,  according  to  the  directions  previously  given. 


TECHNICAL   EXERCISES    WITH    TIN 


147 


2.  Fill  the  simple  cavities  prepared  in  the  bone  handle, 
using  for  one,  the  rolls;  for  another,  the  ropes;  for  the  third, 


Fig.  183. — Filling  the  step  cavity  in  Fig.  184. — Building  the  non-cohesive 

the  end  of  the  bone  handle  with  cylinders  cylinders  to  the  level  of  the  step.     The 

(non-cohesive).     Adapting  the  cylinders  matrix  is  not  shown. 
to  the  seat. 

the  ribbons;  the  fourth,  the  cylinders;  and  the  fifth,   the 
cushions. 


Fig.  185. — The  direction  of  the  cyUnders  is  changed  and  the  rest  of  the  filling 
completed  in  the  manner  illustrated. 

3.  (a)  Take  a  measurement  of  the  circumference  of  the 
handle  at  the  end  containing  the  compound  mortise  form,  and 
from  thin  German  silver  construct  a  matrix  to  be  used  in 


148  FILLING   MATERIALS 

filling  this  cavity,  (b)  Place  the  matrix  in  position  and  fill 
the  cavity  with  cylinders. 

Directions. — (i)  Prepare  cylinders  large  enough  for  three 
of  them  to  cover  the  seat,  when  condensed  against  that  wall, 
and  slightly  longer  than  the  distance  from  the  matrix  to  the 
imaginary  axial  wall,  when  laid  on  the  seat,  with  one  end  toward 
the  matrix  and  the  other  toward  the  axial  wall.  (2)  Place  the 
cylinders  in  position,  and  condense  with  wedge-shaped,  ser- 
rated hand  pluggers,  wedging  the  middle  one  in  between  the 
other  two  (Fig.  183).  (3)  Place  in  more  cylinders,  and 
continue  thus  until  the  filling  is  nearly  on  a  level  with  the  top 
of  the  step  (Fig  184).  (4)  Fill  the  balance  of  the  cavity 
as  if  it  were  a  simple  cavity,  laying  the  cylinders  in  the 
opposite  direction  to  that  used  in  filling  the  first  portion  of 
the  cavity,  viz.,  with  one  end  lying  on  the  step  and  on  that 
portion  of  the  filling  already  condensed,  and  the  other  end 
pointing  toward  the  end  of  the  handle  (Fig.  185). 

4.  Burnish  and  polish  all  of  the  fillings. 

GOLD 

Characteristics. — Gold,  for  filling  cavities,  should  be  pure. 
In  its  pure  state,  uncontaminated,  it  is  cohesive.  By  cohe- 
siveness  is  meant  the  property  which  causes  separate  parti- 
cles, when  brought  in  contact,  to  cling  to  one  another.  Gold 
possesses  this  property  to  a  higher  degree  than  any  other 
metal.  It  is  taken  advantage  of  in  building  fillings,  by  weld- 
ing the  various  pieces  together  in  the  cold  state,  by  means  of 
the  plugger.  Gold  and  tin  are  the  only  metals  possessing 
to  any  degree  this  property  of  cohesiveness  or  weldability 
in  the  cold  state. 

Classification. — Gold,  for  filling  purposes,  is  classified  into 
two  varieties,  as  far  as  its  minute  or  microscopic  structure  is 
concerned. 


CHARACTERISTICS   OF   GOLD  1 49 

1.  Fibrous  gold. 

2.  Crystalline  gold. 

If  these  two  forms  be  examined  under  the  microscope, 
the  fibrous  forms  are  seen  to  consist  of  numerous  fibers  inter- 
lacing each  other  in  every  direction;  while  the  crystalline 
forms  appear  more  granular  in  character.  For  this  reason 
the  fibrous  forms  make  the  stronger  fillings,  although  they 
have  a  tendency  to  draw  away  from  cavity  walls  while  being 
manipulated,  owing  to  a  certain  amount  of  resilience  or  spring 
in  the  fibers.  The  crystalline  forms  do  not  possess  this 
tendency,  and  are  more  easily  manipulated,  but  are  deceptive 
and  treacherous  preparations  for  students'  use  on  account  of 
their  easy  working  properties. 

I.  Fibrous  Gold. — Fibrous  golds  are  supplied  in  the  form 
of  foil  or  sheets  4  inches  square,  ranging  number  2,  3,  4,  5, 
6,  8,  10,  20,  30,  40,  60  and  120.  The  higher  numbers  are 
rolled  out  by  the  manufacturer  from  an  ingot,  while  the  lower 
numbers  are  beaten  by  machinery. 

Fibrous  gold  is  classified  into  (a)  Cohesive;  (b)  Semi- 
cohesive;  (c)  Non-cohesive. 

(a)  The  cohesive  foils  are,  after  being  rolled  or  beaten, 
annealed  by  heat  and  put  up  in  books  containing  1/8  oz. 
Before  using,  the  dentist  usually  re-anneals  them,  as  they  will 
in  time  lose  much  of  their  cohesive  property  on  exposure  to 
the  atmosphere,  accumulating  gases,  which  may  be  driven  off 
by  heat. 

(b)  The  non-cohesive  foils  have  deposited  on  their  sur- 
face certain  substances,  such  as  iron,  sulphur,  or  phosphorus, 
which  destroy  their  cohesive  property. 

(c)  Some  foils  are  suppHed  as  semi-cohesive,  in  wliich 
the  cohesive  property  is  not  developed  to  its  fullest  extent. 
These  are  preferred  by  some  operators.     The  non-cohesive 


150  FILLING   MATERIALS 

and  semi- cohesive  forms  are  also  supplied  in  1/8  oz,  books, 
the  numbers  running  the  same  as  the  cohesive  foils. 

2.  Crystalline  Gold. — There  are  many  varieties  of  this 
form  made  by  various  manufacturers,  all  of  which  are  highly 
cohesive,  and  receive  different  names.  Watfs  Crystal  Gold, 
Solila,  and  Corona  are  preparations  supposed  to  be  both 
fibrous  and  crystalline  in  nature.  These  preparations  are 
not  in  sheet  form,  but  are  supplied  in  strips,  bricks,  mats  and 
similar  shapes. 
Advantages  of  Cohesive  Gold. 

1.  Insolubility. 

2.  Adaptability  to  cavity  walls. 

3.  Great  crushing  resistance  and  edge  strength. 

4.  Freedom  from  molecular  change. 

5.  Capability  of  polish. 
Disadvantages. 

1.  Color. 

2.  High  conductivity. 

3.  Difficulty  of  manipulation. 

It  will  be  seen  that  cohesive  gold  more  nearly  fills  the  re- 
quirements of  an  ideal  filling  material  than  any  other  substance 
yet  introduced,  its  chief  disadvantage  being  its  objectionable 
color.  Until  something  less  conspicuous,  having  the  neces- 
sary lasting  qualities,  is  introduced,  though,  it  will  continue 
to  maintain,  as  it  has  in  the  past,  its  position  as  King  of  filling 
materials. 

Indications  for  Use. — Gold  may  be  placed  in  any  portion 
of  the  mouth  where  proper  access  may  be  obtained,  where  its 
color  is  not  objectionable,  and  the  strength  of  cavity  walls 
permits. 

Non-cohesive  gold  may  be  used,  on  account  of  its  rapidity 
of  manipulation,  in  simple  cavities  with  four  strong  walls,  lo- 
cated on  surfaces  not  subject  to  wear.     It  may  also  be  used 


MANIPULATING   COHESIVE    GOLD 


151 


in  combination  with  cohesive  gold,  for  beginning  fillings  on 
the  gingival  wall  in  proximal  cavities,  or  on  the  pul])al  or 
axial  wall  in  others,  as  a  time-saver.  It  is  not  indicated  on 
surfaces  subjected  to  the  stress  of  mastication,  or  for  contour 
work.  Cohesive  gold,  though,  is  now  used  almost  exclusively, 
on  account  of  its  great  crushing  resis-  ^^^^^ ===5^7-  ---— ^--.^ 
tance,  its  ability  to  contour  and  to  be  ^^^s^h^^^^^^^l 
built  out  over  long  bevels  to  thin  edges,  '"    "    '        ^ 

and  also  on  account  of  greater  famil- 
iarity on  the  part  of  modern  operators 
with  its  working  properties. 

METHOD  OF  WORKING  COHE- 
SIVE GOLD 


Annealing. — Annealing  is  for  the 
purpose  of  driving  off  volatile  surface 
impurities,  and  rendering  soft.  There 
are  two  methods,  as  follows,  viz., 

I.  Cut  the  gold  into  small  pieces, 


Fig.  186. — Kerr  flame  shield 
and  gold  annealer  with 
alcohol  lamp. 


and  lay  on  the  tray  of  a  gold  annealer, 
thus  preventing  contact  with  the  im- 
pure gases  of  the  flame,  as  well  as  the  tendency  to  overheating 
and  irregular  annealing.  The  best  form  of  annealer  is  the 
electric,  though  good  results  are  obtained  with  the  ordinary 
forms,  constructed  for  use  on  the  alcohol  lamp  or  Bunsen 
burner  (Fig.  186). 

2.  Grasp  the  gold  near  one  end  with  foil  carriers,  and  pass 
back  and  forth  over  the  flame  of  an  alcohol  lamp  or  Bunsen 
burner.  Then  grasp  at  another  point,  and  repeat  the  pro- 
cedure, heating  the  gold  to  a  dull  red  color,  being  careful  not 
to  overheat  or  melt  any  portion.  There  are  llircc  disadvan- 
tages in  this  method,     (a)  The  danger  of  overheating  or  melt- 


152  FILLING   MATERIALS 

ing  the  gold,  rendering  it  brittle  and  destroying  its  softness, 
(b)  The  danger  of  overheating  one  part  and  underheating 
another,  (c)  The  danger  of  gases  from  an  impure  gas  flame,  or 
a  charred  wick  of  an  alcohol  flame,  destroying  some  of  the  nat- 
ural cohesive  property  of  the  gold.  The  point  first  grasped 
by  the  pliers  is  not  annealed  because  the  handles  of  the  pliers 
carry  off  the  heat  at  that  point,  hence  the  necessity  of  grasping 
at  a  new  point  after  the  first  annealing,  and  repeating  the  proc- 
ess to  prevent  the  occurrence  of  partially  annealed  spots  in 
the  gold,  with  the  resultant  tendency  to  pitting  in  the  filling. 

The  use  of  a  gold  annealer  is  the  most  satisfactory  method. 
If  a  mica  or  soapstone  tray  is  used,  the  student  should  be  careful 
to  see  that  the  flame  of  the  lamp  is  given  sufficient  heat  to  properly 
anneal  the  gold,  else  poor  fillings  from  failure  to  bring  out  its  full 
cohesive  property  will  be  the  result. 

Gold  Pluggers. — Gold  pluggers  are  made  with  numerous 
serrations  in  their  face,  these  serrations  being  of  a  wedge  or 
pyramidal  shape.  A  set  of  gold  pluggers  should  possess 
serrations  of  the  same  size  in  each  instrument,  in  order  that 
when  change  of  instruments  is  made  during  the  gold-building 
operation,  the  pyramids  may  properly  interdigitate  (see  Figs. 
88,  89  and  90).  In  case  instruments  with  different  size  ser- 
rations are  used,  when  a  change  to  a  new  instrument  is 
made,  the  surface  of  the  gold  should  be  gone  over  with  the 
new  instrument  before  adding  a  fresh  piece  of  gold. 

There  are  three  principal  methods  of  plugging  cohesive 
gold: 

1.  By  means  of  hand  pressure. 

2.  By  the  use  of  the  hand  mallet. 

3.  With  some  form  of  mechanical  mallet. 

For  starting  fillings,  hand  pressure  alone  should  be  used, 
while  for  building  the  main  body  of  the  fiUing,  either  the  hand 
mallet  or  some  form  of  mechanical  mallet  is  utilized.     For 


MANIPULATING    COHESIVE    GOLD 


153 


Fig.  187.  Fig. 

Fig.  187. — Series  of  illustrations  showinK  the  steps  in  filling  a  "gingival  third" 
cavity  on  an  incisor  with  cohesive  gold.  The  cavity  form  is  more  clearly  illustrated 
in  Fig.  141,  a  box-shaped  cavity  with  four  definite  point  angles.  First,  fill  two  of 
the  point  angles. 

Fig.  1S8. — Then  build  gold  along  the  connecting  line  angle,  uniting  that  first 
placed  in  the  two  convenience  angles. 


Fig.  189.  Fig.  190.  Fig.  191. 

Fig.  189. — Carry  the  gold  along  the  gingivo-axial  line  angle  over  into  the  mesio- 
gingivo-axial  point  angle,  anchoring  it  there. 

Fig.  190. — Then  build  along  the  mesio-axial  line  angle  over  into  the  mesio-inciso- 
axial  point  angle,  completely  filling  the  latter. 

Fig.  191. — Continue  the  process  as  outlined  in  the  previous  illustrations  and  com- 
petely  fill  the  cavity,  building  to  proper  fullness  and  making  sure  that  the  margins 
are  covered. 


154 


PILLING   MATERIALS 


operations  in  the  technic  laboratory,  the  student  may  confine 
himself  to  hand  pressure  and  the  hand  mallet,  as  very  excellent 
work  may  be  done  by  this  method,  although,  if  desired,  the 
automatic  mallet  may  be  used  in  addition.  The  operations 
may  be  performed  with  cohesive  tin  instead  of  gold,  and 
excellent  practice  obtained  in  that  manner.  The  student 
should  perform,  though,  at  least  a  few  gold-building  opera- 
tions (Figs.  187,  188,  189,  190  and  191). 

General  Directions  for  Proximal  or  Proximo-Occlusal 

Cavities 

I.  Take  up  a  small  piece  of  gold,  and  carry  it  by  means 
of  the  foil  carriers,  into  the  point  angle  farthest  distant, 
holding  it  in  position  with  a  gold  holder  in  the  left  hand. 


Fig.  192.  Fig.  193. 

Fig.  192. Stages  in  filling  a  proximal  cavity  on  an  incisor  tooth  with  cohesive 

gold.  First  fill  the  Unguo-axio  gingival  and  the  labio-axio-gingival  point  angles  with 
a  half  milUmeter  plugger  by  means  of  hand  pressure.  ,       .     . 

Fig.  193. — Unite  the  two  portions  of  gold  by  bmlding  along  the  gmgivo-axial 
line  angle'.  Then  change  to  a  3/4  millimeter  plugger  and  condense  with  mallet 
force. 

2.  Condense  thoroughly  with  hand  pressure,  by  means 
of  a  half  miUimeter  gold  plugger,  directed  equally  toward 
the  three  walls  forming  the  point  angle,  continuing  to  hold  in 


MANIPULATING  COHESIVE  GOLD 


155 


position  with  the  gold  holder  until  the  point  angle  is  filled, 
when,  if  the  angle  is  properly  prepared,  the  gold  will  remain 
where  placed  (Fig.  192). 


Fig.  194.  Fig.  1Q5. 

Fig.  194.. — Build  the  gold  out  to  full  contour  along  the  axial  wall,  keeping  the  lingual 
portion  in  advance. 

Fig.  195. — Fill  the  incisaFpoint  angle  and  unite  it  to  the  main  body  of  gold,  com- 
pleting the  filling  on  the  labial  side. 


Fig.  196. — Proximo-occlusal 
cavity  in  a  bicuspid  tooth,  pre- 
pared for  a  gold  filling. 


Fig.   197. — The     gingival     point 
angles  filled. 


3.  Repeat  the  same  procedure  in  the  opposite  convenience 
angle  (Fig.  192). 

4.  Build  the  gold  along  the  connecting  line  angle,  con- 


156 


FILLING  MATERIALS 


densing  equally  against  the  two  walls  which  form  the  line 
angle  (Fig.  193),  when  the  gold  is  now  thoroughly  anchored 
in  position. 

5.  Changing  to  a  3/4-millimeter,  or  i -millimeter  plugger, 


Fig.  198. — The  gingival  wall 
covered. 


Fig.  199. — Building    along    the 
axial  wall. 


Fig.  200. — The  top  of  the  step  Fig.  201. — Covering    the_  pulpal 

nearly  reached.  wall  (the  step) . 

depending  on  the  size  of  the  cavity,  condense  thoroughly 
with  hand  mallet,  or  other  form  of  mallet. 

6.  Build  the  gold  along  the  axial  wall  in  proximal  cavities 
not  involving  the  angle,  until  the  other  point  angle  is  reached. 


MANIPULATING   COHESIVE   GOLD 


157 


when  it  is  filled  separately  as  before  with  hand  pressure,  then 

condensed  with  the  mallet  and  afterward  united  to  the  main 

body  of  gold  (Figs.  194  and  195).     In  proximo-occlusal  cavities 

the  same  procedure  is  followed  until  the 

top  of  the  step  is  reached.     Then  fill 

the  con\'enience  angles  separately  at  the 

far  end  of  the  step,  later  uniting  them, 

and  then  building  the  gold  across  the 

step  and  uniting  it  with  the  first  portion 

of  the  filling  (Figs.  196,  197,   198,  199, 

200  and  201). 

7.  Build  the  rest  of  the  filling  to 
proper  restoration  of  contact  and  occlu- 
sion form,  leaving  an  excess  of  gold 
over  the  cavo-surface  angle,  and  the 
balance  of  the  surface  to  allow  for  fin- 
ishing (Fig.  202). 

8.  After  Condensation. — Go  over  the  entire  filling  with 
a  small  foot  plugger,  and  thoroughly  condense. 


Fig.  202— The  two  portions 
united  and  the  filling  com- 
pleted. 


Ten  Rules  for  Plugging  Cohesive  Gold 

1.  Pluggers. — Use  pluggers  ranging  from  1/2  to  i  milli- 
meter in  size,  1/2  millimeter  for  starting  in  convenience 
angles,  and  larger  sizes  up  to  i  millimeter  for  building. 

2.  Stepping. — Step  the  plugger  in  definite  lines,  moving 
it  only  a  distance  of  the  diameter  of  its  face,  after  each  thrust 
or  blow,  to  avoid  bridging  and  imperfect  condensation 

3.  Condensing. — Pack  the  gold  in  small  pieces  and  thin 
layers,  condensing  each  layer  thoroughly  by  the  stepping 
process,  to  assure  thorough  condensation. 

4.  Direction. — Pack  in  the  general  direction  of  the  long 
axis  of  the  tooth,  wherever  possible,  in  order  to  avoid  lateral 


158 


FILLING   MATERIALS 


strain  on  the  pericementum  and  to  place  the  layers  of  gold  in 
a  plane  with  the  plane  of  the  forces  of  occlusion,  so  that  the 
crushing  stress  may  be  resisted  to  the  utmost  (Fig.  203). 

5.  Angle  of  Force. — Incline  the  shaft  of  the  plugger  about 
6  centigrades  from  the  lateral  walls  of  the  cavity,  and  pack 
from  the  center  toward  the  walls. 

6.  Contour. — In  proximal  cavities  build  each  layer  out  to 
full  contour,  to  avoid  the  necessity  of 
"pasting"  gold  on  afterward,  with  re- 
sultant weakening  of  the  surface  of  the 
filling. 

7.  Lingual  Wall. — In  proximal  cavi- 
ties in  anterior  teeth,  build  the  lingual 
portion  in  advance,  finishing  on  the 
labial  side,  and  see  that  the  lingual 
margin  is  thoroughly  covered,  as  each 
layer  is  adapted  (see  Figs.  194  and  195). 

8.  Margins. — Do  not  allow  the 
plugger  to  come  in  contact  with  the 
margins,  on  account  of  danger  of  frac- 
ture of  the  enamel,  but  interpose  a 
layer  of  gold  before  the  blow  is  struck. 

9.  Annealer. — Use  a  gold  anneal er, 
with  the  flame  adjusted  to  give  sufficient  heat. 

10.  Wedging. — In  packing  toward  the  lateral  walls, 
wedge  the  gold  in  between  the  wall  approached  and  the  layer 
being  condensed,  in  order  that  the  filling  may  be  gripped  by  the 
natural  resilience  or  elasticity  of  the  dentin. 


Fig.  203. — Showing  the 
gold  built  in  thin  laminae 
and  placed  in  a  direction  to 
best  resist  the  force  of  oc- 
clusion.   ; 


Technical  Exercises 


Fill  several  of  the  prepared  cavities  on  the  technic  form,  or 
in  the  extracted  teeth,  with  cohesive  foil. 


POLISHING   FILLINGS  I59 

Advantages  of  Non-Cohesive  Gold. 

1.  Insolubility. 

2.  Adaptability  to  cavity  walls. 

3.  Ease  and  rapidity  of  introduction. 

4.  Capability  of  polish. 
Disadvantages. 

1.  Color. 

2.  Non-weldability  and  consequent  lack  of  crushing  re- 
sistance, with  the  result  that  it  is  not  indicated  on  surfaces  ex- 
posed to  mastication  and  cannot  be  contoured. 

3.  High  conductivity. 

For  the  method  of  preparation  and  working  of  non-cohe- 
sive gold,  the  reader  is  referred  to  the  description  of  tin  (see 
page  145),  these  two  materials  being  worked  after  the  same 
method. 

METHOD  OF  POLISHING  FILLINGS 

I.  Fillings  in  Pit  and  Fissure  and  Gingival  Third  Cavities. 
— (a)  Remove  the  excess  with  Black's  or  Pichler's  trimming 
knives,  "flexo"  or  Black's  files,  carborundum  stones,  Gem 
points  or  sand  and  emery  disks,  depending  on  the  size,  loca- 
tion and  shape  of  the  filhng.  The  general  direction  of  the 
cutting  should  be  toward  the  margins.  Do  not  use  rough  stones 
as  the  outline  of  the  cavo-surface  angle  is  approached,  for 
fear  of  damaging  the  margins;  changing  to  knives,  fine  liles. 
Gem  stones  or  disks  for  this  purpose.  Trim  or  grind  the  filling 
down  until  the  original  shape  of  the  tooth  is  restored,  the 
operation  on  occlusal  surfaces  frequently  requiring  the  appli- 
cation of  much  esthetic  taste  as  well  as  mechanical  skill  to 
carve  grooves  and  cusps  to  their  original  anatomical  form, 
(b)  Polish,  first  with  garnet  and  then  with  cuttle-fish  disks, 
in  locations  where  these  will  readily  reach,  finally  going  over 


i6o 


PILLING   MATERIALS 


Fig.  204. — Gold  burnishers. 


Fig,  205. — Removing  the  excess  at  the  gingival  portion  with  a  Black  knife. 


POLISHING   FILLINGS 


i6i 


the  surface,  if  a  specially  high  finish  is  desired,  with  crocus 
disks,  or  with  chamois,  felt,  or  moose-hide  buffers,  dipped  in 
whiting  or  rouge.  In  pits  and  fissures,  where  the  disk  is 
not  applicable,  after  the  final  shaping  of  the  fiHing,  the  sur- 
face may  be  gone  over  with  finishing  burs,  which  will  give 
a  high  burnish;  or,  if  preferred,  the  use  of  wood  points  and 
wet  pumice  may  be  resorted  to,  finally  going  over  the  sur- 
face again  with  the  chamois,  felt  or  moose-hide  wheels  carry- 
ing whiting  or  rouge. 

2.  Fillings  in  Proximal  Cavities,     (a)  The  Gingival  Por- 
tion.— After  thorough  burnishing  (Fig.  204),  the  excess  at  the 


Fig.  206. — Application  of  the  file  to  the  gingival  portion. 

gingival  portion,  up  to  a  point  slightly  gingival  to  the  con- 
tact point,  is  first  removed  by  means  of  a  saw  in  a  Wilson  or 
Kaeber  saw  frame,  or  by  the  use  of  keen  Pichler  or  Black 
knives.  This  portion  is  then  gone  over  with  the  Black 
files,  or  the  Rhein  approximal  trimmers  until  the  filling'  is 
flush  with  the  gingival  margin  (Figs.  205  and  206). 

(b)  The  Buccal  or  Labial  and  Lingual  portions  then  receive 
attention,  the  excess  being  removed  by  the  use  of  the  knives, 


l62 


FILLING   MATERIALS 


Fig.  207. — Filing  the  buccal  and  lin- 
gual portions. 


Fig.  20S. — Use  of  the  stone  on  the 
occlusal  portion. 


Fig.     209. — Polishing    with    the      Fig.  210. — Application  of  the  polishing  strip  to 
disk.  the  inter-proximal  portion. 


POLISHING    FILLINGS 


163 


the  files,  or,  where  convenient,  small  stones,  finishing  burs, 
sand  and  emery  disks  (Fig.  207). 

(c)  The  Occlusal  or  Incisal  portions  next  receive  attention 
in  the  same  manner,  leaving  the  contact  point  untouched. 
(Fig.  208). 

(d)  The  entire  filling  is  then  gone  over  again,  with  the 
exception  of  the  contact  point,  with  the  finer  polishing  strips 
and  disks,  using  the  disks  only  on  the  labial,  buccal,  lingual. 


Fig.  211. — Polishing  the  contact  point. 

incisal  or  occlusal  margins,  utilizing  the  strips  for  the  shaping 
of  the  inter-proximal  portion  (Figs.  209,  210). 

(e)  The  contact  point  should  now  remain  as  a  small  marble 
contact,  as  nature  intended  it,  and  is  now  gone  over  (being 
careful  not  to  flatten  it)  with  a  fine  linen  polishing  strip, 
making  increased  separation,  if  necessary,  for  this  purpose. 
(Fig.  211). 

(f)  In  case  a  still  higher  finish  is  desired,  the  exposed 
surfaces  are  now  gone  over  with  whiting  or  rouge  on  the 
buffers. 


CHAPTER  V 

THE  TREATMENT  OF  PULPS  AND  THE  OPENING  AND 
FILLING  OF  PULP  CHAMBERS  AND  CANALS 

General  Considerations. — The  pulp  is  situated  in  the  pulp 
chamber  and  canals,  which  it  completely  fills.  It  sends  out 
numerous  prolongations,  the  dentinal  fibrillae,  which  penetrate 
the  dentin  to  the  dento-enamel  junction,  and  in  some  cases 
enter  the  enamel.  The  enamel  is  a  low  conductor  and  acts  as 
a  protective  covering  to  the  pulp  and  the  dentinal  fibrillae, 
preventing  the  contact  with  and  the  transmission  of  sensations 
of  heat  and  cold,  electricity,  and  chemical  substances.  When 
the  enamel  is  intact  and  the  pulp  healthy,  the  tooth  is  not 
sensitive  to  ordinary  variations  in  temperature,  the  applica- 
tion of  a  mild  electric  current,  or  the  presence  of  the  chemical 
substances  usually  found  in  the  mouth,  such  as  sweets  and 
.  acids.  If,  however,  through  the  action  of  decay  or  other, 
causes,  the  enamel  be  lost  and  the  dentinal  fibrillae  be  sub- 
jected to  the  action  of  these  agents,  they  soon  become  ab- 
normally responsive  to  them,  transmitting  these  sensations  to 
the  pulp,  which  soon  becomes  irritated,  and  a  diseased  condi^ 
tion  of  its  substance  supervenes. 

1.  If  the  condition  receive  early  treatment,  the  resultant 
fulness  in  the  arteries  of  the  pulp  (Arterial  Hyperaemia)  be  re- 
lieved and  the  lost  enamel  and  dentin  be  compensated  for, 
by  the  application  of  a  non-conducting  filling,  the  pulp  may 
be  permanently  restored  to  its  normal  condition. 

2.  If  allowed  to  continue,  the  increased  supply  of  blood  in 
the  arterial  system  of  the  pulp  is  dammed  back  into  the  veins 
(Venous  Hyperaemia)  and  this  condition  supervening,  finally 

164 


DISEASES    OF    THE    PULP  1 65 

results,  on  account  of  the  pressure  produced  in  the  vessels,  in 
the  passage  of  a  portion  of  the  blood  into  the  interstices  of  the 
pulp  tissue,  with  the  result  that  a  condition  of  Inflanmiation  is 
established.  When  Venous  Hyperaemia  or  Inflammation  is 
present,  the  only  alternative  is  the  destruction  and  removal  of  the 
pulp. 

3.  If  the  condition  be  still  further  neglected,  germs,  con- 
stantly present  in  the  mouth,  make  their  entrance  into  the 
pulp  tissue,  with  the  result  that  pus  formation  occurs  (Sup- 
puration), or  the  death  of  the  pulp  is  finally  accompHshed 
through  a  process  of  putrefaction,  with  the  formation  of  mal- 
odorous gases  (Putrefactive  Decomposition  or  Moist  Gan- 
grene). If,  however,  germs  do  not  enter,  the  pulp  will  die  a 
natural  death  from  lack  of  nourishment  (its  blood  supply 
being  interfered  with)  and  the  condition  of  Dry  Gangrene  is 
established. 

4.  If  these  latter  conditions  supervene,  there  is  then  always 
the  possibility  of  the  pathological  condition  extending  through 
the  apical  foramen,  with  the  resultant  production  of  disease 
processes  in  the  tissues  of  the  apical  space,  and  the  formation 
of  an  Alveolar  Abscess. 

The  diseases  of  the  pulp  mentioned  above  are  progressive 
in  character  and  may  be  briefly  described  as  follows: 

1 .  Arterial  Hyperaemia. — An  increased  supply  of  blood  in 
the  arteries  of  the  pulp,  resulting  in  over-fullness  and  disten- 
tion of  these  vessels,  with  consequent  pressure  on  the  nerves 
and  resultant  pain. 

2.  Venous  Hyperaemia.— The  blood  is  dammed  back  into 
the  veins,  with  the  production  of  the  same  conditions  in  these 
vessels  and  increased  pain  from  pressure. 

3.  Inflammation. — The  pressure  in  veins  and  arteries  re- 
sults in  the  passage  of  the  blood  plasma  and  corpuscles  through 
their  walls  into  the  interstices  of  the  pulp  tissue. 


1 66  THE    TREATMENT    OF    PULPS 

4.  Suppuration. — The  corpuscles  and  the  surrounding 
pulp  tissue  are  broken  down  and  transformed  into  pus,  through 
the  action  of  germs,  which  have  entered  by  way  of  the  blood 
stream. 

5.  Moist  Gangrene. — (Putrefaction.)  The  blood  current 
becomes  stagnant  and  finally  ceases,  on  account  of  the  pres- 
sure in  the  vessels  passing  through  the  minute  apical  foramen. 
Death  of  the  tissues  occurs  from  lack  of  nourishment,  putre- 
factive decomposition  and  destruction  occurring  through 
the  action  of  germs,  with  the  formation  of  malodorous 
substances. 

6.  Dry  Gangrene. — Germs  do  not  enter,  death  of  the  tis- 
sues occurring  without  suppuration  or  putrefaction,  from 
strangulation  and  lack  of  nourishment. 

7.  Alveolar  Abscess. — The  putrescent  material  infects 
the  tissues  of  the  apical  space,  with  resultant  pus  formation, 
breaking  down  and  destruction  of  these  parts. 

The  above  conditions  may  be  classified  as  follows,  viz. : 
I.  Vital  Pulps. 

(A)  Pulps  capable  of  being  restored  to  the  normal  (Arterial 
Hyperaemia) . 

(Venous  Hyperaemia) 


(B)  Pulps  incapable  of  being  re- 
stored to  the  normal. 


(Inflammation) 
(Suppuration) 


2.  De-Vital  Pulps. 

(A)  Pulps  uninfected.     (Dry  Gangrene.) 

(B)  Pulps  in  a  state  of  putrefaction  and  infection.     (Moist 
Gangrene.) 

(C)  Pulps  with  apical  complications.     (Alveolar  Abscess.) 
Avoidance  of  Pressure. — In  cases  of  exposure  (a  minute 

opening  through  the  wall  of  the  pulp-chamber),  the  vital  pulp 
rebels  against  the  application  at  the  point  of  exposure  of  the 
slightest  amount  of  pressure,  so  that  during  the  treatment  of 


ESTABLISHMENT   AND   MAINTENANCE    OF    ASEPSIS 


167 


these  conditions,  great  delicacy  of  touch  and  the  absolute 
avoidance  of  pressure  is  essential. 

Adoption  of  Aseptic  Precautions. — Owing  to  the  fact  that 
the  sahva  and  the  decay  present  in  cavities  is  highly  infected 
with  germs,  whenever  an  exposure  of  the  pulp  occurs,  these 
germs  enter  the  pulp  chamber  and  infect  the  pulp  tissue,  pro- 
ducing what  is  known  as  a  Septic  con- 
dition. The  pulp  is  infected,  then,  in 
all  cases  of  pulp  exposure,  and  there  is 
also  a  possibility  of  these  germs  entering 
to  the  pulp  through  thin  layers  of  den- 
tin in  the  floor  of  cavities,  by  way  of  the 
dentinal  tubules,  even  in  those  cases  in 
which  the  pulp  is  not  exposed.  In  the 
conditions  of  Suppuration  and  Moist 
Gangrene,  highly  infective  micro-organ- 
isms are  always  present.  This  being 
the  case,  it  becomes  necessary  in  treat- 
ing these  conditions  in  the  mouth  to 
adopt  measures  to  prevent,  as  far  as 
possible,  the  entrance  of  these  germs 
by  absolutely  and  permanently  exclud- 
ing the  saliva  from  the  cavity;  or,  in 
case  the  germs  are  already  present,  to 
destroy  them  by  the  application  of  cer- 
tain drugs  known  as  Antiseptics  and  Germicides,  which  will 
either  inhibit  their  further  growth  or  totally  destroy  them. 
These  measures  are  known  as  Aseptic  Precautions,  because 
they  prevent  or  relieve  the  septic  condition,  and  consist  of 
the  application  of  the  rubber  dam  in  all  cases  (Fig.  212,  also 
see  Figs.  115  and  116),  and  the  use  of  antiseptics  on  the  tis- 
sues being  operated  upon,  as  well  as  on  the  instruments 
used. 


Fig. 


212. — Bicuspid  rubber 
dam  clamps. 


1 68  THE   TREATMENT    OF   PULPS 

(i)  TREATMENT  OF  VITAL  PULPS 

(A)  Pulps  Capable  of  being  Restored  to  the  Nonnal. — 

The  treatment  is  known  as  Conservative  treatment,  and  de- 
pends on  whether  the  decay,  when  present,  has  extended  to 
the  pulp  chamber,  constituting  the  condition  known  as 
Exposure  of  the  Pulp,  or  whether  it  has  not  produced  this 
condition.  If  the  pulp  be  not  exposed,  the  treatment  applied 
is  known  as  Pulp  Protection;  if  the  pulp  be  exposed,  the  opera- 
tion of  Pulp  Capping  may  be  resorted  to. 

1.  Pulp  Protection. — (a)  Under  "aseptic  precautions," 
establish  the  outline  form  of  the  cavity,  remove  the  decay, 
make  slight  retentive  form,  and  seal  into  the  cavity  with  base 
plate  gutta  percha  or  cement,  a  small  pledget  of  cotton 
moistened  with  an  antiseptic  and  anodyne  (pain  reliever), 
such  as  eugenol  or  oil  of  cloves,  (b)  At  the  end  of  24  or  48 
hours,  if  pain  is  relieved,  remove  the  dressing  under  ''aseptic 
precautions,"  place  a  cement  intermediate  in  position  and  fill. 

2.  Pulp  Capping. — (a)  Repeat  the  procedure  as  in  "(a)" 
under  Pulp  Protection,  (b)  Remove  the  dressing  at  the  end 
of  24  or  48  hours  under  aseptic  precautions,  (c)  Swage  on  a 
soft  block  of  wood  by  means  of  a  round-end  burnisher,  a  thin 
concavo-convex,  German  silver  disk,  of  the  size  and  shape  to 
cover  the  orifice  of  the  exposure,  (d)  Fill  the  concave  side  of 
the  disk  with  a  thin  paste  of  zinc  oxid  and  oil  of  cloves,  and 
gently  place  the  cap,  with  the  concave  side  down,  over  the 
exposure,  by  means  of  a  small  pair  of  dressing  pliers.  Avoid 
pressure,  (e)  Cover  the  cap  with  a  thin  mix  of  cement, 
avoiding  pressure,  and  complete  the  filling  with  cement  mixed 
to  a  thicker  consistency. 

(B)  Pulps  Incapable  of  Restoration  to  the  Normal. — The 
treatment  is  known  as  Radical  treatment,  and  consists  in  the 
adoption  of  one  or  the  other  of  the  following  procedures,  viz., 


DEVITALIZATION   OF   THE   PULP  1 69 

(i)  Devitalization. 

(2)  Anesthetization, 
(i)  Devitalization. 

l^echnic. — (a)  Under  aseptic  precautions  establish  the  out- 
line form,  remove  the  decay  and  make  the  cavity  slightly  re- 
tentive, avoiding  pressure  on  the  pulp,  (b)  If  the  pulp  is 
aching,  place  gently  over  the  exposure  a  pledget  of  cotton  sat- 
urated with  an  anodyne,  such  as  eugenol  or  clove  oil,  and  seal 
(avoiding  pressure)  with  base  plate  gutta  percha  or  cement, 
allowing  it  to  remain  for  from  24  to  48  hours,  (c)  Remove 
the  dressing  under  aseptic  precautions,  and  gently  place  di- 
rectly over  the  exposure,  or  slightly  to  one  side,  with  a  pair  of 
dressing  pliers,  a  small  pledget  of  cotton  or  piece  of  asbestos, 
on  which  has  been  placed  a  minute  amount  of  arsenical  paste. 
(d)  Seal,  avoiding  pressure,  with  gutta  percha  or  cement,  and 
allow  to  remain  from  one  to  seven  days  (usually  two  days),  at 
the  end  of  which  time  the  vitality  of  the  pulp  is  destroyed,  and 
it  may  be  painlessly  removed. 

Arsenical  Paste  is  a  mixture  of  arsenic  trioxid  with  cocaine 
hydrochlorid  and  other  drugs  for  the  relief  of  pain.  The 
arsenic  trioxid  gradually  produces  death  of  the  pulp  through 
a  process  of  inflammation,  finally  causing  strangulation  of 
the  vessels  by  cutting  off  the  blood  supply  at  the  apical 
foramen.  Its  action  is  usually  painful,  hence  its  combination 
with  cocaine  and  other  pain-alleviating  drugs.  If  the  mi- 
nutest amount  of  arsenic  trioxid  escapes  from  the  cavity 
and  comes  in  contact  with  the  gums,  it  will  produce  inflam- 
mation and  death  of  these  parts  (arsenical poisoning),  which 
is  liable  to  extend  to  the  bony  tissues,  hence  great  care  must 
be  observed  in  placing  arsenical  dressings  to  see  that  they 
are  perfectly  sealed. 
(2)  Anesthetization.     (Pressure  anesthesia.) 

Cocaine  has  the  property  of  temporarily  depriving  the 


lyo  THE    TREATMENT    OF   PULPS 

tissues  of  sensation.  When  forced  into  the  tissues  of  the  pulp, 
that  organ  is  for  a  time  anesthetized,  when  it  may  be  painlessly 
removed. 

Technic. — (a)  and  (b)  Perform  the  same  procedures  as 
described  under  the  same  headings  for  "devitahzation."  (c) 
Place  a  small  piece  of  cocaine  hydrochlorid  in  the  bottom  of 
the  cavity,  and  after  adding  a  drop  of  sterile  water,  when  it 
will  be  dissolved,  cover  it  with  a  pledget  of  cotton,  (d)  Cut 
a  piece  of  soft,  unvulcanized  rubber  of  a  size  sufficient  to  fill 
the  cavity,  and  with  a  large  amalgam  plugger  or  smooth 
burnisher,  slowly  and  gradually  apply  pressure,  thus  forcing 
the  cocaine  solution  into  the  pulp,  constantly  maintaining 
pressure  until  it  does  not  elicit  pain,  when  the  rubber  and 
cotton  are  removed  and  the  pulp  is  ready  for  extirpation  (re- 
moval) .  The  rubber  is  placed  so  that  it  acts  as  a  washer  and 
prevents  the  backward  flow  of  the  cocaine  solution. 

(2)  TREATMENT  OF  DE-VITAL  PULPS 

(A)  Pulps  Uninfected  (Dry  Gangrene). — The  pulp  has  not 
been  exposed  to  external  influences,  hence  is  not  infected  and 
simply  remains  in  the  sound,  undecayed  tooth,  or  under  an 
old  fining,  in  a  dry,  shrivelled  condition.  The  treatment  con- 
sists in  its  removal  under  aseptic  precautions,  with  immediate 
root  filling,  or  the  sealing  in  the  canals  for  two  or  three  days,  of 
cotton  containing  a  bland  antiseptic,  such  as  phenol  or  5  per 
cent,  solution  of  formalin,  after  which  they  are  ready  for 
filling. 

(B)  Pulps  in  a  State  of  Putrefaction  (Moist  Gangrene). 
— A  large  number  of  germs  are  present,  the  pulp  tissue  is 
rapidly  being  transformed  into  a  putrefying  mass  and  gases  of 
a  disagreeable  odor  are  being  formed,  through  the  process  of 
putrefactive  decomposition,  all  of  this  constituting  a  highly 


TREATMENT   OF   DE-VITAL   PULPS  171 

septic  condition.  The  treatment  consists  in  the  application, 
under  aseptic  precautions,  of  agents  which  will  destroy  the 
germs  (antiseptics  and  germicides),  and  chemically  transform 
the  putrefactive  material  and  gases  into  harmless  substances. 

Technic. — (a)  Under  aseptic  precautions,  establish  the 
outline  form,  remove  the  decay,  and  make  the  cavity  retentive, 
(b)  Open  the  pulp  chamber  and  remove  the  bulbous  portion  of 
the  pulp,  (c)  Seal  in  the  pulp  chamber,  by  means  of  base 
plate  gutta  percha  or  cement,  on  a  pledget  of  cotton,  a  mixture 
of  equal  parts  of  formalin  and  cresol,  known  as  forme -cresol. 
(d)  At  the  end  of  from  24  to  72  hours,  take  out  the  dressing 
under  aseptic  precautions,  and  remove  the  remainder  of  the 
pulp  from  the  canals,  (e)  Place  in  each  canal,  and  also  in  the 
pulp  chamber,  cotton  containing  the  formo-cresol  mixture, 
and  seal  the  cavity  as  before,  (f)  After  an  interval  of  from  24 
to  72  hours,  remove  the  dressings  under  aseptic  precautions 
and  fill. 

(C)  Pulps  with  Apical  Complications  (Alveolar  Abscess.) 
— The  putrefying  material  and  the  germs  have  been  forced  by 
the  expansion  of  the  gases  being  formed,  through  the  apical 
foramen  into  the  tissues  of  the  apical  space.  The  treatment, 
in  addition  to  that  outlined  above,  consists  in  the  application 
of  measures  to  relieve  the  conditions  at  the  end  of  the  root,  and 
will  not  be  considered  here. 

Technical  Exercises 

1.  Surround  the  apices  of  the  roots  of  the  teeth  on  which 
the  pulp  treatments  and  the  exercises  in  canal  work  are  to  be 
performed  with  wax,  to  simulate  the  tissues  of  the  apical  space. 
Mount  the  teeth  in  plaster  of  Paris,  molding  and  carving  it  to 
a  convenient  size  and  shape  for  handling. 

2.  Establish  the  outline  form  of  the  cavities,  remove  the 


172  THE   TREATMENT   OF   PULPS 

decay  and  render  slightly  retentive,  exposing  the  pulps,  if  not 
already  exposed. 

3.  Seal  antiseptic  and  anodyne  treatments  in  several 
teeth. 

4.  Perform  the  operation  of  pulp  capping  on  several  teeth. 

5.  Perform  the  operations  of  arsenical  devitalization  and 
pressure  anesthesia  on  others. 

OPENING  PULP  CHAMBERS  AND  CANALS 

One  or  the  other  of  the  following  conditions  will  be  present. 

1 .  The  pulp  has  been  previously  anesthetized  with  cocaine, 
or  devitalized  with  arsenic. 

2.  The  pulp  is  devital  and  uninfected;  or  in  a  state  of 
putrescence  and  infected  with  germs. 

Rule  I. — When  cavities  are  present,  make  the  approach 
to  the  pulp  chamber  through  the  cavity. 

Rule  2. — ^In  sound  teeth,  or  teeth  with  perfect  fillings, 
enter  through  the  center  of  the  lingual  surface  of  incisors  and 
cuspids,  the  mesial  pit  of  bicuspids  and  the  central  fossa  of 
molars. 

Rule  3. — Enlarge  the  opening,  whether  through  an  already 
existing  cavity  or  one  artificially  made,  until  convenient 
access  to  the  pulp  chamber  and  canals  is  obtained;  at  the  same 
time,  avoid  weakening  the  tooth  by  too  much  cutting. 

Rule  4. — Make  the  walls  of  the  cavity  and  pulp  chamber 
continuous  and  smooth,  though  not  necessarily  parallel  or  on 
the  same  plane. 

Rule  5. — Make  the  walls  of  the  pulp  chamber  and  canals 
continuous  and  smooth. 

Technic  for  Opening  into  Pulp  Chambers 

I.  In  Sound  Teeth. 

(a)  Perforate  the  enamel  with  a  i -millimeter  bi-bevelled 


OPENING   INTO   PULP   CHAMBERS 


173 


dentate  fissure  bur  (made  by  bevelling  a  dentate  fissure  bur 
on  two  sides),  or  a  small  spear-point  drill,  in  the  handpiece  of 
the  engine. 

(b)  Enlarge  the  opening  with  a  larger  sized  bur  or  drill. 

(c)  Perforate  the  dentin  gradually  to  the  pulp  chamber, 
alternating  first  mth  the  smaller  and  then  the  larger  sized 
burs  or  drills,  avoiding  the  danger  of  breakage  by  frequently 
withdrawing,  and  continuing  in  this  manner  until  the  pulp 
chamber  is  reached. 


Fig.  213,  Fig.  214. 

Fig,  213. — Series  of  illustrations  showing  the  method  of  opening  into  the  pulp 
chamber  and  canal  through  the  lingual  surface  of  the  anterior  teeth. 
■   First  drill  through  the  enamel  and  dentin  until  the  pulp  chamber  is  reached; 
then  gradually  enlarge  the  opening  with  burs  or  drills  ot  increasing  diameter. 
Fig.  214. — Then  increase  the  size  of  the  entrance  by  inclining  the  shaft  of  the 
fissure  bur  first  toward  the  gingival  and  then  toward  fhe  incisal  portions. 

(d)  Enlarge  the  opening  with  the  same  instruments  until 
convenient  access  is  obtained,  and  then  remove  the  entire 
wall  of  the  pulp  chamber,  extending  the  cuttings  out  until 
the  horns  of  the  pulp  chamber  are  included. 

(e)  Make  the  walls  of  the  cavity  and  pulp  chamber 
continuous  and  smooth. 

(f)  Remove  the  contents  of  the  pulp  chamber  and  all 
debris  (Figs.  213,  214,  215  and  216). 


174 


THE   TREATMENT   OP   PULPS 


2.  Through  Cavities  of  Decay. 

(a)  Establish  the  outhne  form,  remove  aU  decay,  and 
make  the  cavity  shghtly  retentive. 

(b)  If  the  pulp  is  not  exposed,  penetrate  the  dentin  to  the 
pulp  chamber,  with  the  drills  or  the  bi-bevelled  dentate 
fissure  bur. 

(c)  Remove  the  wall  of  the  pulp  chamber  with  a  hoe 


Fig.  215.  Fig.  216. 

Fig.  215. — Straighten  the  approach  to  the  canal  on  the  lingual  side  by  means  of 
the  fissure  bur.  The  passage  of  a  small  broach  to  the  apex  has  thus  been  rendered 
easy  by  the  removal  of  the  small  shoulder  at  the  entrance  to  the  same  shown  in  the 
preceding  illustration. 

Fig.  216. — Place  the  dentate  fissure  bur  in  position  and  open  the  chamber  to  its 
incisal  extremity,  thus  removing  the  horns  of  the  pulp  chamber  with  their  contents. 
The  walls  of  the  cavity,  pulp  chamber  and  canal  are  now  continuous  and  smooth. 

excavator  or  a  dentate  fissure  bur,  extending  the  cuttings 
until  the  horns  of  the  chamber  are  included. 

(d)  In  incisors  and  cuspids  straighten  the  approach  to 
the  canal  by  extending  the  cavity  in  the  lingual  or  gingival 
direction  with  a  dentate  fissure  bur. 

(e)  In  upper  molars,  straighten  the  approach  to  the 
mesio-buccal  canal  by  extending  the  cavity  with  a  fissure  bur 
toward  the  mesio-buccal  cusp,  and  enlarging  the  pulp  chamber 
in  the  same  direction  by  means  of  the  same  instrument  or  a 
cleoid  excavator. 


OPENING   INTO   THE   CANALS  1 75 

(f)  Make  the  walls  of  the  cavity  and  pulp  chamber  con- 
tinuous and  smooth. 

(g)  Remove  all  debris. 

Technic  for  Opening  into  Canals 

The  anterior  teeth,  both  upper  and  lower,  have  one  root 
canal  which  is  continuous  with  the  pulp  chambers,  and  as  a 
rule  easily  found  after  the  approach  has  been  straightened,  as 
already  described.  The  upper  first  bicuspids  have,  in  the 
majority  of  instances,  two  canals,  one  buccal  and  one  lingual, 
although  in  probably  one-third  of  the  cases,  only  one  canal  is 
present.  The  upper  second  and  the  lower  bicuspids  present 
as  a  rule  a  single  canal.  In  the  upper  molars  there  are  present 
three  canals,  a  mesio-buccal,  disto-buccal,  and  lingual,  placed 
at  the  angles  of  a  triangle  (molar  triangle) .  The  lower  molars 
have  a  mesio-buccal  and  a  mesio-lingual  canal,  located  in  the 
mesial  root  and  a  distal  canal  situated  in  the  distal  root.  The 
canals  in  the  lower  bicuspids  are  more  or  less  continuous  with 
the  pulp  chambers,  while  those  in  the  upper  bicuspids  and  the 
upper  and  lower  molars  are  separate  and  distinct  from  the 
chamber,  opening  from  its  floor  with  more  or  less  constricted 
orifices.  Owing  to  the  presence  of  these  constrictions,  and 
the  small  size  of  the  buccal  canals  in  the  upper  molars  and 
the  mesial  canals  in  the  lowers,  difficulty  is  frequently  ex- 
perienced in  locating  their  entrances  and  following  them  with 
instruments  to  their  termination. 

Technic. — (a)  Locate  the  entrance  and  explore  the  canals 
with  a  small,  round,  smooth  broach. 

(b)  Enlarge  the  orifice  with  a  Kerr  or  Downie  tapered 
canal  reamer,  a  small  bud-shaped  bur,  a  twist  broach,  spiral 
broach  reamer,  or  a  Donaldson  canal  cleanser  (Figs.  217 
and  218). 


176 


THE   TREATMENT   OF   PULPS 


(c)  Make  the  walls  of  the  pulp  chamber  and  canals  con- 
tinuous. 

(d)  Pass  a  small  canal  cleaner  to  the  apex,  or  until  it 
binds,  withdraw  slightly,  give  it  a  half  turn  and  then  remove 
from  the  canal,  bringing  away  as  much  of  the  pulp  tissue  as 
possible.  Continue  thus,  using  larger  and  larger  sizes,  as  the 
canal  will  permit,  broaching  or  rasping  the  sides  of  the  canals, 
and  gradually  enlarging  them.    Carry  the  broach  just  to  the 


Fig.  217.  Fig.  218. 

Fig.  217. — Cavity  of  decay  on  the  mesial  surface  of  a  central  incisor  opening  into 
the  pulp  chamber.  It  woiJd  be  difficult  to  pass  a  broach  to  the  apex  owing  to  the 
shoulders  on  the  mesial  side  of  the  entrance  to  the  canal. 

Fig.  218. — Straighten  the  approach  to  the  canal  by  enlarging  its^entrance  on  the 
mesial  side  with  a  dentate  fissure  bur,  a  Kerr  tapered  canal  reamer  or  a  spiral  broach 
reamer.  Then  enlarge  the  cavity  toward  the  incisal  and  remove,  the  horns  of  the 
pulp  chamber.     The  cavity,  chamber  and  canal  are  now  continuous  and  smooth. 

apex,  and  no  further.  The  passage  of  the  broach  through  the 
apical  foramen  will  produce  irritation  in  the  tissues  of  the 
apical  space,  and  consequently  should  be  avoided. 

(e)  Small  Canals. — In  small  canals,  where  entrance  with 
a  barbed  canal  cleanser  is  difl&cult,  change  to  a  spiral  broach 
reamer,  or  a  twist  broach.  Start  with  the  smallest  size,  care- 
fully boring  in  and  withdrawing  in  a  direction  which  will  tend 
to  straighten  the  canal,  gradually  changing  to  larger  and 


ENLARGING  SMALL  CANALS 


177 


larger  sizes,  until  the  canal  is  thoroughly  opened  (Figs.  219  and 
220). 

(f)  In  difficult  cases  a  50  per  cent,  solution  of  sulphuric  acid, 
or  better,  phenol-sulphonic  acid  (which  latter  more  readily 
clings  to  the  broach),  carried  into  the  canal  on  the  broach, 
will,  by  uniting  chemically  with  the  calcium  salts  of  the  dentin, 

soften  the  walls  of  the  canals  and 
render  the  work  easier.  Its  ac- 
tion should  be  neutralized  on 
completion  of  the  operation  with 
a  saturated  solution  of  sodium 
bicarbonate. 

(g)  Remove  all  debris, 
(h)  After  the  proper  medic- 
inal treatment  has  been  given, 
depending    on    the    conditions 


Fig.  219. — Reaming    the    canal  with  a      Fig.  220. — Enlarging    the   canals  of  a 
Kerr  twist  broach.  lower  molar  with  a  Nub  broach. 


present,  as  already  described,  the  canals  are  ready  for  drying 
and  filling. 

Wrapping  Cotton  on  Smooth  Broaches. — The  method 
varies,  depending  on  whether  the  cotton,  containing  some 
medicament,  is  to  be  temporarily  left  in  the  canal,  or  whether 


178  THE    TREATMENT    OF   PULPS 

it  is  to  be  immediately  withdrawn  on  the  broach,  as  in  swab- 
bing or  drying  the  canal. 

1.  When  the  Cotton  is  to  be  left  in  the  Canal. — (a)  Place 
a  few  wisps  of  cotton  on  the  pulp  of  the  forefinger  of  the  left 
hand,  (b)  Lay  a  round  or  square  smooth  broach  on  the 
cotton,  allowing  the  end  of  the  cotton  to  extend  slightly 
beyond  the  point  of  the  broach,  (c)  Rotate  the  broach  to  the 
right  with  the  thumb  and  fingers  of  the  right  hand,  at  the 
same  time  rolling  the  cotton  in  the  same  direction  with  the 
thumb  and  forefinger  of  the  left  hand.  Roll  the  cotton  fairly 
tightly  at  the  point  of  the  broach  and  loosely  the  rest  of  the 
way.  (d)  Fold  the  slight  excess  of  cotton  left  at  the  end  of 
the  broach  over  that  already  rolled  and  roll  it  in  the  same 
direction  as  before,  so  as  to  thoroughly  cover  the  point  of  the 
broach,  (e)  Carry  the  broach  containing  the  cotton  as  far 
as  possible  into  the  canal  to  be  treated,  (f)  Rotate  a  turn  to 
the  left,  at  the  same  time  withdrawing  it  a  short  distance, 
when  the  cotton  will  be  disengaged,  (g)  Pack  the  cotton 
further  into  the  canal  by  pushing  the  broach  slightly  forward, 
and  then,  again  rotating  to  the  left,  withdraw  a  short  distance, 
continuing  in  this  manner  until  the  broach  is  entirely  free  of 
the  canal  and  the  cotton  remains  in  position. 

2.  When  the  Cotton  is  to  be  Withdrawn  on  the  Broach. — 
(a)  File  off  the  sharp  point  of  the  broach  or  nick  it  off  with  a 
pair  of  scissors,  leaving  it  slightly  roughened,  so  that  the  cotton 
will  be  held  more  securely,  (b)  Wrap  the  broach  with  the 
cotton  as  already  described,  except  that  it  should  be  wrapped 
tightly  throughout  the  procedure,  (c)  Carry  the  broach  into 
the  canal  and  on  withdrawal,  rotate  to  the  right,  when  the 
cotton  will  remain  on  the  instrument,  (d)  To  remove  the 
cotton  from  the  broach  grasp  it  firmly  between  the  thumb 
and  forefinger  of  the  left  hand  and  twist  the  broach  to  the 
left  with  the  right  hand. 


TECHNIC   OF   FILLING   CANALS  179 

FILLING  CANALS 

It  is  necessary  that  the  canals  to  be  filled  have  been 
thoroughly  treated  under  aseptic  precautions,  the  sahva 
excluded  throughout  the  course  of  treatments,  all  debris  and 
remaining  decomposable  material  removed,  and  absolute 
dryness  accomplished. 

Drying  Canals. — Wrap  a  few  shreds  of  cotton  on  a  smooth 
broach  and  swab  out  the  canal,  absorbing  all  moisture  possible 
by  changing  the  cotton  on  the  broach  as  often  as  necessary 
to  accomplish  the  result.  Then  force  in  a  current  of  hot  air 
from  the  heated  bulb  of  the  chip  blower,  or  some  of  the  various 
forms  of  root  canal  driers,  until  absolute  dryness  is  accom- 
plished, when  the  canals  are  ready  to  fill. 

Requisites  of  a  Good  Canal-filling  Material. — It  should  be 

1.  Non-irritant  to  the  tissues  of  the  apical  space. 

2.  Indestructible  in  the  fluids  entering  at  the  apex,  or 
through  the  pulp  chamber  (in  case  of  leaky  fillings) . 

3.  Easy  of  introduction. 

4.  Antiseptic  in  character. 

5.  Colorless. 

6.  Easy  of  removal  (in  case  of  trouble  arising  later). 
Rule. — Endeavor  always  (a)  to  completely  seal  the  apical 

foramen,  (b)  avoid  forcing  the  material  through,  and  (c)  to 
so  adapt  the  material  to  the  walls  of  the  canal  that  all  air  will 
be  excluded  and  the  canal  for  its  entire  length  be  hermetically 
sealed.  This  is  not  always  possible,  owing  to  the  varying 
size,  tortuosity  and  inaccessibility  of  canals,  but  if  the  ideal 
stated  in  the  above  rule  be  constantly  aimed  at,  the  operator 
will  at  least  have  the  satisfaction  of  a  clear  conscience. 

Technic. 

Two  methods  will  be  described,  one  for  large  and  one  for 
small  canals. 


i8o 


THE   TREATMENT   OF   PULPS 


I.  FILLING  LARGE  CANALS.— Gutta-percha  points. 

(a)  Measure  the  diameter  of  the  apical  foramen.    Pass  a 

small,  smooth  broach,  or  canal  plugger,  to  the  apex.  If  it 
passes  through,  change  to  a  size  larger,  or  two  sizes  larger, 
continuing  until  one  is  found  which  will  pass  jiist  short  of  the 
apical  foramen. 

(b)  Measure  the  length  of  the  canal.  Pass  a  small, 
smooth  broach,  or  a  hooked  extractor,  if  the  size 
of  the  cana]  will  permit,  to  the  apical  foramen, 
catching  the  hook  over  the  apex,  if  the  latter  in- 
strument is  used.  A  small  piece  of  cardboard  or 
rubber  dam  encircling  the  shaft  of  the  broach 
is  moved  until  it  is  in  contact  with  the  crown  of 
the  tooth,  when,  the  broach  being  withdrawn,  a 
measurement  of  the  length  of  the  tooth  is  seen, 
and  a  guide  as  to  the  length  of  the  canal  is  ob- 
tained (Fig.  221), 

(c)  Select  a  tapering  Gutta-percha  cone  (Fig. 
222),  approximating  the  size  of  the  canal,  and 
cut  off  its  end,  until  it  is  the  size  of  the  apex  as 
previously  determined. 

(d)  Cut  off  a  section  about  3  or  4  millimeters 
in  length,  which  will  be  utilized  for  filling  the 
apical  portion.  Also  cut  the  rest  of  the  cone  into 
small  sections  for  filling  the  balance  of  the  canal. 

(e)  Wrap  a  smooth  broach  with  a  few  shreds  of  cotton,  dip 
it  in  eucalyptol  and  freely  moisten  the  canal.  Avoid  too  much 
cotton  on  account  of  the  tendency  to  form  a  piston  and  force 
the  solution  through  the  apex.  Remove  all  excess  of  eiicalyp- 
tol  with  a  broach  wrapped  with  dry  cotton,  leaving  the  wall 
slightly  moistened  with  eucalyptol. 

(f)  Catch  up  the  smallest  section  of  a  Gutta-percha  cone 
on  the  end  of  a  warmed  root  canal  filler,  dip  it  in  eucalyptol, 


Fig.  221. — 
Measuring  the 
length  of  the 
canal. 


FILLING   SMALL   CANALS  l8l 

remove  the  excess,  carefully  carry  it  to  place  and  tamp  to 
position,  withdrawing  the  plugger,  when  the  apical  portion  is 
filled. 

(g)  Continue  the  procedure  with  the  next  largest  pieces  in 
order,  carefully  packing  to  position,  and  warming  the  largest 
pieces,  until  the  canal  is  filled;  then  seal  the  pulpal  opening 
with  a  warm  plugger  or  burnisher. 


Fig.  222. — Gutta-percha  canal  points. 

(h)  Fill  the  pulp  chamber  with  Oxyphosphate  of  Zinc 
Cement. 

2.  FILLING  SMALL  CANALS.— (Gutta-percha  and 
Chloro-percha). 

(a)  Moisten  the  canal  with  eucalyptol  as  before. 

(b)  Dip  a  small,  smooth  broach,  on  which  are  wound  a  few 
fibers  of  cotton,  into  chloro-percha  and  pump  the  canal  as 
fuU  as  possible,  avoiding  forcing  the  material  through  the 
apex. 

(c)  Force  in  on  a  smooth  broach,  squared  on  the  end,  a 
small  section  of  a  gutta  percha  cone,  as  large  as  the  canal  will 
accommodate,  and  seal  the  entrance  to  the  canal  with  a  warm 
canal  plugger  or  burnisher. 

Making  Gutta-percha  Points. — These  may  be  obtained 
ready  prepared.  An  excellent  method  of  making  them  in  the 
laboratory  of  various  sizes  and  shapes  is  as  follows:  Warm  a 


l82  THE    TREATMENT    OF   PULPS 

clean,  smooth  cement  slab.  Cut  off  a  small  section  of  Gutta- 
percha base-plate,  and  after  heating  it  over  the  alcohol  lamp, 
roll  into  a  cone  between  the  clean  thumb  and  forefinger. 
Lay  it  on  the  warm  slab,  and  with  a  warmed,  broad,  clean 
cement  spatula,  roll  it  out  quickly  into  a  long  rope.  As  the 
rope  gets  longer  and  longer  it  will  be  convenient  to  hold  one 
end  by  pressing  it  on  the  slab  while  using  the  spatula  in  the 
other  hand,  and  working  it  with  a  back  and  forth  movement. 
The  roll,  as  it  approaches  the  proper  size,  may  be  cut  into 
sections,  and  then  each  section  may  be  rolled  separately  into 
any  size  desired.  They  may  then  be  cut  into  convenient 
lengths,  with  the  hot  spatula  or  a  knife. 

Technical  Exercises 

1.  Open  the  pulp  chambers  and  canals  of  the  teeth  pre- 
pared under  Pulp  Treatments,  the  presence  of  the  wax  cover- 
ing the  apices  of  the  roots  serving  as  a  guide  to  prevent  the 
passage  of  the  canal  instruments  too  far. 

2.  Seal  in  the  pulp  chamber  and  canals  several  cotton 
dressings  containing  anodyne,  antiseptic  and  formo-cresol 
treatments. 

3.  Remove  the  dressings,  dry  and  fill  the  canals  after  the 
two  methods  described. 


CHAPTER  VI 
SUGGESTIONS  TO  THE  TEACHER 

^^  He  teaches  who  gives,  and  he  learns  who  receives.  There 
is  no  teaching  until  the  pupil  is  brought  into  the  same  state  or 
principle  in  which  you  are;  a  transfusion  takes  place;  he  is  you, 
and  you  are  lie;  then  is  a  teaching,  and  by  no  unfriendly  chance 
or  bad  company  can  he  ever  lose  the  benefit. '' — Emerson. 

The  first  requisite  to  successful  teaching  of  the  subjects 
of  Dental  Anatomy  and  Operative  Technics  is  enthusiasm  for 
the  work  on  the  part  of  the  teacher,  and  the  second  is  the 
ability  to  instill  this  enthusiasm  into  each  individual  member 
of  the  class.  The  teaching  of  the  subject  is  an  art,  as  is  the 
teaching  of  any  other  subject,  which  is  only  acquired  by 
intelligent  observation  and  close  study.  The  idea  that 
teachers  are  born  and  not  made  is,  to  a  large  degree,  an 
erroneous  one.  A  great  man,  when  asked  to  define  genius, 
replied  to  the  efi'ect  that  it  was  one  part  natural  aptitude  and 
nine  parts  hard  work  in  a  given  field  of  endeavor.  The 
writer  prefers  to  subscribe  to  this  theory  as  applied  to  teaching. 

It  is  an  excellent  plan  to  meet  the  class  for  the  first  time 
in  an  informal  manner,  endeavoring  to  learn  the  names  of  the 
students  as  early  as  possible,  so  that  they  may  be  called 
individually  when  speaking  in  the  class  room  or  laboratory. 
A  few  words  of  fatherly  advice  in  regard  to  morality  and 
purity  of  living,  as  well  as  the  early  acquirement  of  studious 
habits,  will  not  be  amiss  and  will  impress  the  class  with  your 
personal  interest  in  their  welfare.  A  short  talk  on  the 
importance  of  a  knowledge  of  the  subject  of  Dental  Anatomy, 

183 


184  SUGGESTIONS    TO    THE    TEACHER 

bringing  out  its  bearing  and  relation  to  other  branches  of 
dentistry,  as  well  as  its  practical  application  in  all  future  work 
and  a  brief  discussion  of  the  noble  and  elevated  character  of 
the  profession,  its  artistic  and  scientific  nature,  as  well  as  its 
broad  scope,  will  be  of  benefit. 

The  student  should  be  given  something  to  do  at  the  first 
meeting  (making  drawings  of  some  point  mentioned  or  taking 
notes)  and  his  interest  not  be  allowed  to  lag  for  lack  of  employ- 
ment, from  this  time  throughout  the  course.  As  few  set 
lectures  as  possible  should  be  given,  rather  assigning  a  lesson 
for  the  next  time  of  meeting,  and  using  an  informal  quiz  and 
explanation  method.  Do  not  talk  at  but  to  and  with  the  stu- 
dent. He  should  bring  his  text-book  to  the  class  and  many 
points  which  have  not  been  fully  brought  out  in  the  text  may 
thus  be  elucidated.  The  book  has  been  bound  in  a  convenient 
size  for  carrying  in  the  pocket. 

Frequent  written  quizzes  are  valuable,  the  notebooks 
being  turned  in  to  the  teacher  for  grading  and  correcting. 
Drawings  and  the  notes,  as  well  as  the  written  quizzes,  should 
be  made  in  a  book  designed  for  the  purpose.  One  of  the  many 
forms  of  loose-leaf  notebook  will  serve  the  purpose  admir- 
ably. The  paper  should  be  unruled  and  of  such  quality  that 
the  drawings  may  present  a  good  appearance.  The  student 
should  be  given  to  understand  that  he  will  be  graded  on  the 
care  and  condition  of  his  notebook,  thus  stimulating  a  habit 
of  neatness. 

At  stated  times  the  oral  quizzes  may  be  transformed  into 
a  hee,  after  the  fashion  of  the  old  spelling  bee.  The  class  is 
divided  into  halves  and  a  number  of  students  from  each  sec- 
tion are  requested  to  come  forward  and  arrange  themselves 
on  opposite  sides  to  uphold  the  honor  of  their  section  in 
demonstrating  their  knowledge  of  the  questions  to  be  asked. 
The  interest  thus  stimulated  is  frequently  gratifying. 


SUGGESTIONS  TO  THE  TEACHER  1 85 

If  the  class  is  large,  the  teacher  should  keep  a  roll  book  of 
his  own,  even  if  other  methods  of  taking  the  roll  are  in  vogue 
in  the  school.  The  habit  of  caUing  the  roll  himself  insures 
early  assembling  and  enables  him  to  more  readily  notice 
individual  delinquency  in  promptness  and  attendance.  A 
diagram  of  the  seats  in  the  classroom  and  of  the  work  benches 
in  the  laboratory,  with  the  students'  names  written  in  their 
proper  places,  is  a  valuable  aid  in  tracing  individual  students 
in  large  classes,  their  attendance,  quiz  marks  and  other  grades 
and  necessary  memoranda  being  kept  opposite  their  names 
on  the  chart,  instead  of  in  an  ordinary  roll  book. 

If  a  student  is  late  he  should  be  quizzed  before  the  period 
is  over;  if  he  is  noticed  talking  or  inattentive  he  should  be 
quizzed;  if  he  is  absent  he  should  be  quizzed  at  the  next 
succeeding  period.  If  this  plan  is  followed,  there  will  soon  be 
little  trouble  in  regard  to  the  above  delinquencies,  as  the  stu- 
dents will  soon  learn  your  method  of  dealing  with  cases  of 
that  kind. 

All  of  the  technic  exercises  should  first  be  performed  and 
explained  by  the  teacher  and  then  copied  by  the  class,  from 
conveniently  displayed  models,  located  about  the  room. 
The  work  should  be  so  mapped  out  that  the  technic  opera- 
tions are  being  performed,  as  far  as  possible,  while  the  talks 
and  quizzes  are  being  given  on  that  subject  and  these  should 
be,  if  possible,  completed  by  the  entire  class  before  the  consid- 
eration of  another  subject.  An  excellent  method  of  dealing 
with  those  disposed  to  lag  behind  is  to  quiz  them  at  every 
opportunity  and  to  inspect  their  technic  work  frequently, 
inquiring  into  the  cause  for  their  backwardness.  A  little 
encouragement,  though,  will  frequently  accomplish  much 
better  results  with  these  individuals  than  rough  methods. 

It  is  a  good  plan  to  have  the  technic  work  deposited  in  the 
teacher's  room  at  the  end  of  each  period,  the  student's  box 


i86 


SUGGESTIONS    TO    THE   TEACHER 


being  numbered  and  kept  in  its  own  place.     In  this  way  his 
application  and  progress  may  be  more  closely  watched. 

An  excellent  plan  in  mapping  out  the  course  is  to  figure 
out  the  number  of  weeks  and  the  number  of  hours  in  each  week 
to  be  devoted  to  the  work.  In  this  way  the  teacher  may 
readily  note  the  progress  the  class  is  making  and  keep  the  work 
moving  along  to  schedule  time. 


Fig. 


223. — Enlarged  aluminum  model  used  by  the  author  for  teaching    dental 

anatomy. 


Enlarged  models  of  natural  tooth  forms  are  valuable  for 
teaching  Dental  Anatomy  and  these,  with  typical  cavity  prep- 
arations, and  removable  fillings,  are  of  great  service  in  the 
Operative  Technic  course.  The  plan  of  calling  students  from 
the  class  to  point  out  certain  points  of  interest  on  these  en- 
larged forms  works  well.  At  Northwestern  University  Dental 
School  is  a  set,  carved  in  wood,  many  times  enlarged,  and 
mounted  on  a  frame  with  rollers  for  easy  handling.     Typical 


SUGGESTIONS  TO  THE  TEACHER 


187 


cavity  forms  have  been  prepared  in  these  anatomically 
correct  specimens  and  the  wood  fillings  are  made  in  sections, 
so  that  the  various  steps  in  the  filling  operation  may  be  readily 
demonstrated. 

Figures  223  and  224  illustrate  a  model  designed  by  the 
author  and  made  under  his  supervision  by  one  of  his  former 
pupils,  Dr.  C.  H.  Chapman. 


Fig,  224. — Same  model  as  shown  in  Fig.  223  carrying  teeth  with  tj^pical  cavity 

preparations. 


This  model  is  of  aluminum  with  removable  teeth.  There 
is  a  complete  set  of  perfect  natural  tooth  forms.  Black's 
average  measurements,  enlarged.  There  is  also  a  set,  which 
is  interchangeable,  with  typical  cavity  forms,  very  useful  for 
demonstrative  and  display  purposes.  Enlarged  models  are, 
in  the  writer's  opinion,  more  useful  for  demonstrating  pur- 


l88  SUGGESTIONS   TO   THE   TEACHER 

poses  than  the  lantern,  though  where  these  are  not  available, 
the  lantern  is  a  valuable  adjunct. 

At  the  University  of  Southern  California,  Dental  Depart- 
ment, Los  Angeles,  there  is  in  use  an  enlarged  set  of  plaster 
models  designed  by  Professor  H.  Gale  Atwater,  showing  var- 
ious stages  of  decay,  on  which  actual  operations  are  performed 
before  the  class,  with  a  set  of  enlarged  instruments  (Figs. 
225,  226,  and  227),     At  the  University  of  Cahfornia  Dental 


'^^t^ 

■  h 

gjfi-.!- 

m 

1 

Fig.  225. — Dr.  H.  Gale  Atwater's  model  and  instruments.  Both  are  made  to 
Black's  measurements,  25  diameters.  A  model  of  the  lower  teeth,  not  shown,  is  also 
used.  In  the  illustration,  ideal  cavity  forms  have  been  completed.  Enlarged 
matrices  may  be  seen  to  the  right  of  the  picture. 

Department,  San  Francisco,  there  is  in  use  an  enlarged  set 
showing  the  progressive  stages  of  gold-building  operations  in 
colors,  which  should  prove  very  valuable. 

The  collection  of  an  adequate  number  of  extracted  teeth 
is  really  not  such  a  difficult  problem,  if  pursued  in  the  right 
manner.  The  College  catalogue  should  contain  a  clause  in  a 
conspicuous  place,  appealing  to  its  alumni  for  extracted  teeth. 
The  prospective  student  should  also  be  requested,  by  way  of 


SUGGESTIONS   TO   THE   TEACHER 


189 


Fig.  226. — Another  view  of  Dr.  Atwater's  model  and  instruments.  Typical 
cavities  of  decay  are  seen,  wliile  the  instrumentation  incident  to  the  preparation  of  a 
cavity  on  a  molar  wall  be  noticed.  The  various  pathological  conditions  incident  to 
the  formation  of  a  cavity  through  the  orocess  of  caries  (such  as  partially  affected 
dentin,  the  bacterial  zone,  leathery  decay,  brown  caries,  ptomaines  and  food  debris) 
are  imitated  on  these  models. 


Fig.  227. — Another  view  of  the  model  used  in  the  University  of  Southern  CaHfornia, 

Dental  Department. 


190 


Suggestions  to  the  teacher 


678 

Fig.  228. — Excavator  blanks.     Clev.  Dent. 


SUGGESTIONS   TO   THE   TEACHER  19I 

the  catalogue  and  otherwise,  to  bring  extracted  teeth  with  him. 
If  the  members  of  the  class  will  take  a  bottle,  labeled  "Ex- 
tracted Teeth"  to  any  dentist  of  their  acquaintance,  this  pro- 
cedure will  have  the  desired  result  in  most  instances,  whereas, 
if  the  dentist  is  simply  requested  to  save  the  teeth,  he  will  in 
the  majority  of  cases,  forget,  or  neglect  to  do  so.  The  labeled 
bottle,  placed  in  a  convenient  place  in  his  laboratory,  is  a 
constant  reminder. 

A  dental  museum,  in  which  are  mounted  specimens  of 
normal  and  abnormal  tooth  forms,  is  valuable  as  a  teaching 
aid  in  proportion  to  the  number  and  variety  of  the  specimens 
contained  therein  and  the  frequency  with  which  they  are  used. 
The  students  should  be  stimulated  to  deposit  especially  per- 
fect or  anomalous  specimens  in  this  museum,  the  name  of  the 
donor  being  displayed,  which  will  act  as  an  incentive  to  their 
accumulation. 

The  technic  work  in  instrument  making  is,  in  the  opinion 
of  the  writer,  extremely  important.  The  student  should  be 
given  as  much  work  in  the  manipulation  of  steel  as  time  will 
permit.  The  accompanying  illustration  (Fig  228)  of  excavator 
blanks  is  intended  as  an  aid  in  ordering  blanks  of  the  proper 
size.  The  set  of  nine  blanks  (Clev-Dent.)  will  make  the 
entire  set  of  Black's  cutting  instruments,  as  follows,  viz: 

Blank  No.  i.— Nos.  5,  6,  11,  12,  17,  18,  23,  24,  29,  30,  35, 
36,  41,  42,  47,  48,  87,  88. 

Blank  No.  2. — Nos.  2,  3,  4,  8,  9,  10,  16,  22,  27,  28,  33,  34, 
40,  46,  83,  86. 

Blank  No.  3.— Nos.  i,  7,  25,  26,  31,  32,  82,  85,  91,  94. 

Blank  No.  4.— Nos.  81,  84. 

Blank  No.  5. — ^Large  chisels  and  specials. 

Blank  No.  6.~Nos.  15,  21,  53,  54,  59,  60,  65,  66,  71,  72, 
95,  96,  98,  100,  102. 


192 


SUGGESTIONS   TO    THE   TEACHER 


Blank  Xo.  7.— Nos,  13,  14,  19,  20,  37,  38,  39,  43,  44,  45, 
5i>  52,  57,  58,  63,  64,  69,  70,  77,  78,  79,  80,  97,  99,  loi. 

Blank  Xo.  8.— Nos.  49,  50,  55,  56,  61,  62,  67,  68,  73,  74, 
75,  76. 

Blank  Xo.  9. — Nos.  89,  90,  92,  93. 

The  technic  exercises  in  cavity  preparation  and  filling 
may  be  performed  on  natural  teeth  or  on  some  of  the  numerous 


Fig.  229. — The  Typodont.     No.  i. 


technic  forms,  in  the  judgment  of  the  teacher.  If  a  sufficient 
number  of  extracted  teeth  suitable  for  the  purpose  are  avail- 
able there  is  a  great  advantage  in  their  use,  as  the  student  is 
thus  early  familiarized  with  the  cutting  consistence  of  natural 
tooth  structure,  is  taught  where  to  place  his  cavity  walls  in 
their  relation  to  the  pulp,  and  is  enabled  to  perform  proper 


SUGGESTIONS   TO    THE   TEACHER. 


193 


Fig.  230. — The'typodont.    No.  2. 


Fig.  231. — The  odontotype.    Nos.  i  and  2. 


194 


SUGGESTIONS    TO    THE    TEACHER 


Fig.  232. — The  odontotype.     Nos.  6  and  7. 


Fig.  233. — The  Wright  Dental  Manikin.     Designed  by  Dr.  Edwin  P.  Wright. 
A  metallic  head  with  soft  rubber  (removable)  lips  and  cheeks. 


SUGGESTIONS  TO  THE  TEACHER 


19s 


enamel  bevels.  The  princii)al  disadvantage  of  the  technic 
blocks  is  that  they  do  not  allow  a  [)roper  com])rehension  on  the 
I)art  of  the  beginner  of  these  important  points. 

Of  the  technic  forms  available,  the  Typodont,  Lee  S. 
Smith  &  Co.  (Figs.  229  and  230),  and  the  Wenker  Odontotypes 
(Figs.  231  and  232),  are  the  best.  In  making  a  selection  from 
these,  it  should  be  borne  in  mind  that  the  student  should 
comprehend  the  necessity  of  proper  contact  and  occlusion  in 
the  building  of  fillings  and  of  separation  to  accomplish  the 
former.  None  of  these  forms  adequately  provide  for  the 
application  of  all  of  the  principles  mentioned,  but  the  Wenker 


Fig.  234.  Fig.  235. 

Fig.  234. — Wright  manikin.  Rubber  face  piece  removed.  Removable  vulcanite 
teeth.  The  entire  jaws  are  also  removable.  The  head  rests  in  a  ball  and  socket 
joint  and  may  be  fixed  in  any  position. 

Fig.  235. — Wright  manikin.  The  appliance  rests  on  a  telescoping  iron  stand 
which  is  attached  to  the  floor.    The  manikin  is  useful  for  teaching  operative  technics. 

forms  with  ivory  teeth  and  soft  rubber  base  to  allow  for 
separation  are  the  most  valuable  ones  yet  devised. 

At  the  New  York  College  of  Dentistry  there  is  in  use  an 
aluminum  manikin,  which  may  be  fastened  to  the  head-rest 
of  the  chair  or  to  the  laboratory  work-bench.  It  is  an  im- 
provement on  the  Wright  manikin,  (illustrated  in  Figs.  233, 
234  and  235)  for  teaching  operative  technics. 


196  SUGGESTIONS    TO    THE    TEACHER 

At  the  end  of  the  course  the  technic  work  should  be  as- 
sembled in  as  attractive  a  manner  as  possible,  arranging  the 
pieces  in  chronological  order.  The  work  should  be  returned 
to  the  students  at  the  completion  of  their  course,  as  it  will  be 
found  that  they  will  take  a  great  deal  more  interest  in  finishing 
and  assembling,  if  they  know  that  they  will  receive  it  again. 

Every  teacher  desires  to  put  his  own  individuality  into  the 
teaching  of  his  course,  and  without  that  any  course  is  a  failure; 
but  it  is  believed  that  the  suggestions  here  given  will  be  help- 
ful in  formulating  and  systematizing  an  outline  for  the  year's 
work. 

TECHNIC  COURSE  SUGGESTED  BY  THE  AUTHOR 

The  following  table  is  an  outline  of  the  technical  exercises 
described  in  the  previous  chapters.  It  offers  to  the  teacher  a 
wide  scope  in  the  matter  of  selection.  The  exercises  marked 
with  an  asterisk  are  the  ones  which  the  author  recommends. 

DENTAL  ANATOMY 

A.  Drawings. 

*i.  Outline  drawing,  three  diameters,  of  the  labial  surface 
of  the  crown  and  root  of  the  right  upper  central  incisor. 

*2.  Outline  drawing,  three  diameters,  mesial  or  distal 
surface  of  the  crown  and  root  of  the  upper  central  incisor. 

*3.  Shaded  drawing,  three  diameters,  labial  surface  of 
the  upper  central  incisor. 

*4.  Outline  drawing,  three  diameters,  labial  surface  of  the 
crown  and  root  of  the  right  upper  cuspid. 

*5.  Shaded  drawing,  three  diameters,  of  the  labial  sur- 
face of  the  same  tooth. 

*6.  Outline  drawing,  three  diameters,  of  the  buccal  sur- 
face of  the  crown  and  root  of  the  right  upper  first  bicuspid. 


TECHNIC   COURSE   SUGGESTED  BY   THE   AUTHOR  197 

*7.  Outline  drawing,  three  diameters,  of  the  mesial  or 
distal  surface,  crown  and  roots  of  the  same  tooth. 

*8.  Shaded  drawing,  three  diameters,  buccal  surface  of 
the  crown  and  root  of  the  upper  second  bicuspid. 

*9.  Outline  drawing,  three  diameters,  of  the  mesial  or 
distal  surface  of  the  lower  first  bicuspid. 

*io.  Shaded  drawings,  three  diameters,  of  the  occlusal 
surfaces  of  the  upper  first  and  lower  second  bicuspids. 

*ii.  Outline  drawing,  not  to  measurement,  of  the  buccal 
surfaces,  of  the  upper  and  lower  bicuspids,  showing  the  most 
frequent  location  of  the  points  of  the  cusps. 

*i2.  Outline  drawing,  three  diameters,  of  the  buccal  aspect 
of  the  crown  and  roots  of  the  right  upper  first  molar. 

*i3.  Shaded  drawings,  three  diameters,  of  the  occlusal 
surfaces  of  the  right  upper  first,  second  and  third  molars. 

*i4.  Outline  drawing,  not  to  scale,  showing  the  molar 
triangles. 

*i5.  Outline  drawings,  not  to  scale,  of  three  cubical 
figures,  indicating  the  location  of  the  surfaces,  margins  and 
angles  of  the  lower  molars. 

*i6.  Shaded  drawings,  three  diameters,  of  the  buccal  sur- 
faces of  the  crown  and  roots  of  the  left  lower  first  and  second 
molars. 

*  1 7 .  Shaded  drawing,  three  diameters,  of  the  mesial  surface 
of  the  crown  and  roots  of  the  lower  first  molar. 

*i8.  Shaded  drawing,  three  diameters,  of  the  occlusal 
surface  of  the  left  lower  first  molar. 

*i9.  Shaded  drawing,  three  diameters,  of  the  occlusal 
surface  of  the  right  lower  second  molar. 

*2o.  Outline  drawing,  not  to  scale,  showing  the  teeth  in 
occlusion. 

*2i.  Outline  drawing,  not  to  scale,  showing  the  labio- 
lingual  inclination  of  the  upper  and  lower  central  incisors. 


198  SUGGESTIONS  TO  THE  TEACHER 

*22.  Outline  drawing,  showing  the  mesial  inclination  of 
the  same  teeth. 

*23.  Outline  drawing,  showing  the  bucco-lingual  inclina- 
tion, of  the  upper  and  lower  molars. 

*24.  Shaded  drawing,  showing  the  enamel,  dentin,  cemen- 
tum  and  pulp  of  the  upper  central  incisor. 
B.  Carvings. 

1.  Carving  Teeth  in  Plaster. — Carve  to  Black's  measure- 
ments, five  diameters,  the  upper  central  and  lateral  incisors, 
the  upper  cuspid,  upper  first  bicuspid  and  upper  first  mo- 
lar. Preliminary  cavity  preparation  work  is  done  on  these 
later. 

2.  Carving  Teeth  in  Soap. — Carve  all  the  teeth,  upper  and 
lower  of  one  side,  to  exact  measurement. 

*3.  Carving  Teeth  in  French  Chalk. — Carve  to  scale  the 
upper  and  lower  central  and  lateral  incisors,  the  upper  and 
lower  cuspids,  the  upper  first  and  lower  first  and  second  bicus- 
pids, the  upper  first  and  lower  first  and  second  molars. 

4.  Carving  Teeth  in  Ivory. — Carve  to  exact  measurement 
the  upper  central  and  lower  lateral  incisors,  upper  and  lower 
cuspids,  upper  first  bicuspid,  lower  first  and  second  bicuspids, 
upper  and  lower  first  molar,  of  one  side. 

*C.  Sawing  and  Filing  Sections. — Make  one  longitudinal 
and  three  transverse  sections  of  the  upper  and  lower  teeth, 
right  or  left  side. 

D.  Making  Prints. — Make  prints  in  ink  of  the  sections 
cut. 

OPERATIVE  TECHNICS 
A.  Instrument  Making. 


* 


I. 


Make  from  piano  wire  six  smooth  broaches. 


*2.  Make  from  the  same  material  six  hooked  extractors. 


TECHNIC   COURSE   SUGGESTED   BY   THE   AUTHOR  199 

*3.  Perform  the  exercises  on  pages  42,  43  and  44  illustrat- 
ing Annealing,  Hardening  and  Tempering. 

*4.  Make  from  steel  blanks  six  excavators  or  chisels. 

*5.  Make  from  annealed  brass  wire,  13-gauge,  the  blade 
and  shank  of  all  the  excavators  and  chisels  in  the  college  list. 
B.  Cavity  Preparation. 

*i.  Drawings.— Outline  drawings  of  the  outline  form  of 
typical  cavities  in  the  occlusal  surfaces  of  upper  bicuspids, 
lower  bicuspids,  upper  molars,  lower  molars,  and  the  proximal 
surfaces  of  the  anterior  teeth. 

*2.  Preparing  Mortise  Forms. — Carve  to  form  six  cubes 
of  plaster  of  Paris,  2  inches  square,  and  on  these  prepare: 

(a)  The  simple  mortise  form,  one  surface. 

(b)  The  simple  mortise  form,  two  surfaces. 

(c)  The  simple  dovetail  mortise  form,  one  surface. 

(d)  The  simple  dovetail  mortise  form,  two  surfaces. 

(e)  The  compound  mortise  form  (step  form). 

(f)  The  compound  dovetail  mortise  form. 

Study  the  names  of  the  cavity  walls  and  line  and  point 
angles  in  these  imaginary  cavities. 

(g)  Deepen  the  convenience  angles  and  bevel  the  margins. 
*3.  Preparing  Cavities  in  the  Bone  Handle.— Prepare  six 

cavities  in  the  bone  handle,  to  be  later  filled  with  non-cohesive 
tin. 

4.  Preparing  Cavities  on  Enlarged  Plaster  Teeth. — Pre- 
pare six  cavities  on  the  enlarged  plaster  teeth,  carved  in  the 
Dental  Anatomy  Technic  Course. 

5.  Preparing  Cavities  in  Ivory  Teeth. — Prepare  six  cavities 
in  the  ivory  teeth  carved  in  the  same  course.     See  page  31. 

6.  Preparing  Cavities  in  Extracted  Teeth. — Prepare  six 
cavities  in  extracted  teeth.  In  case  sufficient  work  in  sawing 
and  filing  sections  has  not  been  done  to  impress  upon  the 
student's  mind  the  relative  thickness  of  enamel  and  dentin 
and  the  relation  of  the  pulp  chamber  to  the  tooth  surface, 


200  SUGGESTIONS  TO  THE  TEACHER 

the  work  in  cavity  preparation  on  extracted  teeth  may  be 
preceded  by  exercises  in  splitting  natural  teeth  and  a  study 
of  these  points. 

*7.  Preparing  Cavities  on  the  Technic  Form. — Prepare  on 
the  Odontotype  or  the  Typodont  cavities  illustrating  all  the 
various  classes,  to  be  filled  later,  some  with  amalgam,  others 
with  gold. 

C.  Pulp  Treatments. 

*i.  Mount  in  plaster  of  Paris  an  upper  central  incisor, 
a  cuspid,  an  upper  first  bicuspid  (two  roots),  an  upper  second 
bicuspid  (one  root),  an  upper  and  a  lower  molar. 

*2.  Establish  the  outline  form,  remove  the  decay  and  make 
the  cavities  slightly  retentive. 

*3.  Perform  the  operations  of  pulp  capping,  pressure 
anesthesia  and  devitalization  on  these  teeth. 

*4.  Open  the  pulp  chambers  and  canals  and  seal  in  treat- 
ments of  various  kinds,  practising  the  two  methods  of  wrap- 
ping broaches. 

*5.  Dry  and  fill  the  canals. 

*6.  Complete  the  cavity  preparation,  and  place  cement 
intermediates,  building  some  to  step  form. 

D.  Filling. 

*i.  Fill  three  of  the  above  cavities  in  the  treated  teeth 
with  base  plate  gutta  percha  and  three  with  cement. 

*2.  Perform  the  experiment  described  on  page  131  in 
mixing  and  staining  cement. 

*3.  Make  from  tin  foil,  specimens  of  the  roll,  rope,  ribbon, 
cylinder  and  mat. 

*4.  Fill  the  cavities  in  the  bone  handle  with  tin  foil. 

5.  Fill  the  cavities  prepared  in  the  ivory  teeth. 

6.  Fill  the  cavities  prepared  in  the  extracted  teeth. 

*7.  Fill  the  cavities  prepared  on  the  technic  form  with 
amalgam  and  gold. 


NDEX 


Abscess,  alveolar,  165,  166,  171 
Absorbent',  80 
Acid,  lactic,  90 

phcnol-sulphonic,  177 
Acute  angle  hatchet,  112 
Adjuncts  and  accessories,  80 
After-condensation,  157 
Alloy,  131 
Alloys,  135,  136 
Amalgam,  131 
Amalgams,  advantages  of,  132 

classification  of,  134 

disadvantages  of,  133 

properties  of,  132 
Amalgam  plugger,  69,  136 
Anatomy,  dental,  i 
Anesthetization,  169 
Anesthetized,  170 
Angle,  38,  91,  158 

axial  line,  91 

cavo-surface,  91 

of  force,  158 

pulpal  line,  91 
Angles,  centigrade,  51 

in  shanks,  44 

line,  21,  38,  93,  94 

point,  21,  38,  93,  94,  101,  109,   III, 

154 
Angling,  87 
Annealer,  gold,  150 
Annealing,  43,  87,  151 

steel,  42 
Annotating  prints,  36 

sections,  34 
Anodyne,  168,  169 
Antiseptics,  167,  168,  17c,  171 
Apical  section,  36 

space,  171 
Areas,  vulnerable,  97 
Arsenical  paste,  169 
Arterial  hyperc-emia,  164 
Aseptic  precautions,  167 
Astronomical  circle,  50 
Attributes  of  an  ideal  filling   material, 

120 
Automatic  mallet,  71 
Auxiliary  mortise,  102-104,  105,  108 
Average  measurements  of  the  teeth,  10 


Axial,  39,  156 
line  angle,  91 


B 


Barbed  broach,  73,  76 

Bevel,  87,  1 12,  IIS 

Bevels,  5=; 

Bevel  and  polish  enamel  margins,  112, 

IIS 
Beveling,  87,  115 
Bi-bevels,  55 
Bin-angle,  46 

contra-angles,  46 
Binary  (amalgams),  134 
Bistoury,  61 

Black's  measurements,  table  of,  11,  12 
Blade,  44 
Blocks,  bone,  27 

French  chalk,  8,  27 
Block's,  Harper's,  8,  27 

ivory,  8,  27 

plaster,  8,  26 

soap,  8,  26 

Tenney's,  8,  27 

vegetable  ivory,  8,  27 

wood,  8 
Boley  millimeter  gauge,  8,  27,  29,  53 
Bone  handle,  preparing  cavities  in  the, 

116 
Box  form,  no 
Brass,  technic  work  in,  88 
Broach,  73 

barbed,  73,  76 

handle,  76 

holder,  76 

hooked,  73,  75 

nub,  76 

smooth,  73 

twist,  73,  76 
Burnisher,  69 
Burnishers,  engine,  70 
Burs,  59,  60 
Burs,  bi-beveled  dentate  fissure,  172 


Canal  cleanser,  76,  175 
explorer,  73 
explorers,  making,  42 
filling  material,  requisites  of  a  good, 
179 


201 


202 


INDEX 


Carving,  directions  for,  27 

teeth,  26,  27 
Causes  of  decay,  90 
Cavity,  complex,  92,  93 

explorer,  73 

form,  give  the,  100 

gingival  third,  105,  no 

linings,  131 

names,  91 

nomenclature,  91 

of  decay,  90 

pit  and  fissure,  105,  no 

preparation  for  amalgam  work,  137 
steps  in,  95 

simple,  92,  93 
Cavo-surface  angle,  91,  94 
Cement,  127,  128,  129,  130 
Centigrade  angles,  51 

circle,  50 
Centigrades,  51,  S3,  "5 
Centimeter,  50 
Cervical  clamp,  79 

line,  4,  30 

curvature  of,  3  c 
Chisel,  57,  115 
Chloro-percha,  125 
Circle,  astronomical,  50 

centigrade,  50 
Clamp,  79 

cervical,  7 

cotton  roll,  80 

forceps,  rubber  dam,  79 

matrix,  80 

rubber  dam,  79 
Classification  of  amalgams,  134 

of  cavities,  95 

of  filling  materials,  122 

of  instruments,  56 
Class  names,  56 
Cleoid  excavator,  57 
Cohesive  foils,  149 
Cohesiveness,  148 
Compound  mortise,  102,  104,  105,  109, 

in 
Concave  mirror,  81 
Condensing  (gold),  157 

instruments,  67 
Cone-socket  instruments,  55 

pliers,  78 
Conservative  treatment,  168 
Contra  angles,  46 
Convenience  form,  100 
Copper,  134 

metallurgical  properties  of,  134 
Corona,  150 
Crown  sections,  36 
Crushing  resistance,  121: 
Crystallia,  138 


Crystalline  gold,  149,  150 
Cubical  figures,  20 
Curved  sections,  36 
Cushion,  the,  139,  141 
Cutting  instruments,  56 

the  relief  line,  34 
Cylinder,  the,  139,  141 

method,  the,  145 


D 


Decay,  causes  of,  90        *■ 

cavity  of,  90 

remove  the,  100 

technic  for  removing,  100 
Decimeter,  50 
Definition  of  a  human  tooth,  38 

of  steel,  41 
Dental  anatomy,  i 

how  to  study,  i 

how     to     perform     the     technic 

operations,  8 
review  quiz,  38 

instrument  gauge,  51 
Dentinal  fibrillae,  164 
Dento-enamel  junction,  91,  164 
De- vital  pulps,  166,  170 
Devitilization,  169 
Directions  for  carving,  27 

for    making    steel    excavators    and 
chisels,  87 
Discoid  excavators,  56,  57 
Disk,  64 

Double  mortise,  102,  104,  105 
Dovetail  mortise,  102 
Drawings  in  dental  anatomy,  12 

in  outline  form,  98 
Dressing  pliers,  78 
DrUl,  60 

Dry  gangrene,  165,  166,  170 
Drying  canals,  179 
Duplex,  138 


E 

Electric  mallet,  71 
Enamel  hatchet,  57 
Engine  burnishers,  70 

instruments,  44 

mallet,  71 
Enlarged  models,  185,  186,  187,  188,  189 

plaster    teeth,    preparing    cavities 
in  the,  117,  118 
Establish  the  outline  form,  96 
Esthetic,  121 
Ethical,  121 
Eucalyptol,  181 


INDEX 


203 


Excavator,  56,  57 

blanks,  191 
Exercises,  technical,  in  working  steel,  42 

to   illustrate   annealing,   hardening 
and  tempering,  43 
Explorer,  7.3 

canal,  73 

cavity,  73 
Exposure  (of  the  pulp),  166,  168) 
Extension  for  prevention,  97 
Extirpation,  170  ... 

Extracted  teeth,   preparing   cavities   in 
the,  118 


Fermentation,  90 
Fibrous  gold,  149 
File,  62 
Filling,  120 

canals,  179 
large,  180 
small,  181 
materials,  120 

classification  of,  122 
non-plastic,  138 
permanent,  122 
plastic,  123 
temporary,  122 
Floss  silk,  80 
Foil-carrier,  78 
Form,  box,  no 
cavity,  ico 
compound  mortise,   102,   104,  105, 

109,  III 
convenience,  100 
incisal  step,  106,  in 
lingua]  step,  loS,  in 
outline,  96,  99 
resistance,  loi,  103,  105 
retention,  iic,  in 
simple  mortise,  loi,  102,  103,  104, 

108 
step,  108,  109 
Formo-cresol,  171 
Formula  names,  53 
French  chalk  blocks,  8 

chalk  carving  teeth  in,  26 


Guage,  dental  instrument,  51 

Boley  millimeter,  53 
Gem  point,  64 
Germicides,  167,  171 
Germs.  90,  97,  167,  170 
Gilling  twine,  80 
Gingiva,  5,  4° 


Gingival  line,  curvature  of,  30 

margin,  5 
trimmer,  58 

third  cavities,  105 
Give  the  cavity  form,  too 
Gold,  148 

advantages  of  cohesive,  150 
of  non-cohesive,  159 

annealer,  151,  152 

characteristics  of,  148 

classification  of,  148 

cohesive,  149 

crj'Stalline,  149,  15° 

disadvantages  of  cohesive,  150 
of  non-cohesive,  159 

fibrous,  149 

folder,  139 

method  of  working,  151 

non-cohesive,  149,  150 

plugger,  68,  69,  152 

semi-cohesive,  149 
Guard,  the,  49 
Gutta-percha,  123,  124,  125 

H 

Handle,  bone,  116 
Handles,  44,  45-  ^44 
Hand  instruments,  44 

mallet,  70 
Hardening  steel,  43,  88 
Harmonious  color,  120 
Harper's  ivory  blocks,  8,  27 
Hatchet,  acute  angle,  112 

excavator,  56 
Hemp  thread,  80 
High  percentage  alloys,  135 
Hoe  excavator,  57 
Hooked  broach,  73,  75 

extractors,  making,  43 
Hot-air  syringes,  86 
Hyperaemia,  164,  165 


Incisal  step,  in 

form,  106,  in 
Inclination  of  the  teeth,  23,  24,  25,  40 
Inflammation,  165 
Ingot,  132,  138,  149 
Insolubility,  120 

Institute  of  Dental  Pedagogics,  vl,  91 
Instrumentology,  44 
Instruments,  41 

classification  of,  56 

condensing,  67 

cone-socket,  55 


cutting,  56 


204 


INDEX 


Instruments,  engine,  44 

hand,  44 

long  handle,  55 

miscellaneous,  71 

names  of,  55 
Instrument  blanks,  86 

gauge,  dental,  51 

grasps,  46 

making,  86 

parts  of  an,  44 
Intermediates,  128,  130 
Inverted  pen  grasp,  the,  46,  47 
Ivory  blocks,  8 

teeth,  preparing  cavities  in,  118 

vegetable,  8 

carving  teeth  in,  27 

soap,  26 


Jeweler's  broach,  75 


K 


Knife,  63 


Labeling  sections,  34 

Lactic  acid,  9c 

Lancet,  61 

Lifting  stress,  no 

Ligature,  80 

Lime  salts,  90 

Line  angles,  21,  38,  93 

Lines  of  measurement  of  the  teeth,  10 

Lingual  step,  in 

form,  ic8,  in 
Long  handle  instruments,  55 
Longitudinal  sections,  31 
Low  percentage  alloys,  135 

M 

Magnifying  mirror,  81 

Making  gutta-percha  points,  181 
hooked  extractors,  43 
prints  or  silhouettes,  36,  37 
smooth  broaches  and  canal  explor- 
ers, 42 

Mallet,  70 

Mon-angle,  44 

Mandrels,  64 

Margin,  91 

Marginal  outline,  91 

Margins,  names  of,  94 

Matrix,  77,  130 
band,  77 
clamp,  80 
retainer,  77 


Matrices,  137 

Mat,  the,  139,  141 

Measurement  of  the  teeth,  10,  n,  12 

lines  of,  10 
Measurements,  table  of,  11,  12 

the  metric  system  of,  49 
Mechanical  mallet,  71 
Metallurgical  properties,  silver,  tin,  etc.. 

^33  . 
Method  of  mixing  amalgam,  135 

of  packing  amalgam,  136 

of  working  cohesive  gold,  151 

of  polishing  fillings,  159 
Meter,  the  French,  50 
Metric  system  of  measurement,  the,  49 
Micron,  50 
Mid-root  section,  2^ 
Millimeter,  50 

gauge,  8,  27,  29,  S3 
Miscellaneous  instruments,  71 
Mirror,  plane,  81 
ModeUng  in  clay,  25 
Moist  gangrene,  165,  166,  170 
Molar  triangle,  20 
Molecular  change,  121 
Mon-angle,  46 
Mortise,  102 

auxiliary,  102,  104,  105,  108 

compound,  102,  104,  105,  109,  11 1 

double,  102,  104,  105 

dovetail,  102 

simple,  102,  103,  104,  108 
Mounting  sections,  i^;^,  35 


N 


Names  of  instruments,  55 

class,  56 

order,  55 

sub-class,  56 

sub-order,  55 

of  margins,  94 
Nib,  the,  44 
Nomenclature,  90 

of  simple  cavities,  94 

of  complex  cavities,  92 
Non-cohesive  foils,  149 
Non-conductivity,  121 
Non- magnifying  mirror,  81 
Non-plastics,  122 
Non-plastic  filling  materials,  138 
Nub  broach,  76 

O 

Occlusion,  3,  4,  6,  23,  39 
line  of,  23,  39 
curvature  of  line  of,  23 


INDEX 


205 


OdontotyiH',  igj,  lo.S.  '94 

(Jl)eninK  inilp  chambers  unci  canals,  172 

Order  names,  56 

OiiUine  form,  establish  the,  96 

Technic  for  estaljHshinp;  the,  99 

Talm  and  thuml)  f,'ras|),  the,  46,  48 

Palmer's  notation,  4,  9 

Parallelo{j;ram,  15,  21 

Parts  of  an  instrument,  44 

Pen  Kriisji,  the,  46 

Perform  the  toilet  of  the  cavity,  116 

Permanent  lillinK  materials,  122 

Plane  mirror,  Si 

Plaster  blocks,  8,  2() 

carving  teeth  in,  26 

teeth,    preparing    cavities    in    the 
enlarged,  117 
Phenol-sulphonic  acid,  177 
Pit  and  fissure  cavities,  105,  no 
Plastics,  122 
Plastic  alloys    135 

Tdling  materials,  123 
Pliers,  78 

cone  socket,  78 

dressing,  78 

plugging,  78 
Plugger,  68,  157 

gold,  68,  69,  152 

amalgam,  69,  136 
Plugging  pliers,  78 
Pneumatic  mallet,  71 
Point  angles,  21,  38,  93,  109,  in 

diamond,  64 

gem,  64 
Polishing  fillings,  method  of,  159 
Preliminary  polish,  87 
Preparation  of  cavities,  definition  of,  90 
Prevention,  extension  for,  97 
Preparing  cavities  in  the  bone  handle, 
116 

in  the  enlarged  plaster  teeth,  117 

in  the  ivory  teeth,  118 

in  the  extracted  teeth,  118 

in  the  typodont  or  odontotype,  119 

mortise  forms,  102 
Pressure  anesthesia,  169 
Procter  &  Gamble's  ivory  soap,  26 
Properties  of  amalgam,  132 
Pulp  capping,  168 

exposure  of  the,  166 

protection,  130,  168 

treatments,  168 
Pulpal  line  angle,  gi 
Puljis,  treatment  of  vital,  168 
of  dcvital,  170 
uninfected,  170 


Putrefactive  decomposition,  165,    170 
I'utrefaction,  165,  166 


Quadrangle,  46 

contra-anglc,  46 
(^)uarternary  (amalgams),  134 
(^)uinary  (amalgams),  134 
Quick-setting  alloys,  135 

R 

Radical  treatment,  168 
Rasping,  176 
Reamer,  61,  175,  176 
Relief  line,  cutting  the,  34 
Remove  the  decay,  100 
Requisites  of  a  good  canal-filling  mate- 
rial, 179 
Resistance  form,  lor 

rules  for  obtaining,  103 

technic  for  obtaining,  105 
Rest,  the,  49 
Rests  and  guards,  48 
Retention  form,  no,  in 
Rhombic,  20 
Ribbon,  the,  139 

method,  the,  143,  146 
Rights  and  lefts,  55 
Roll,  the,  139 
Rope,  the,  139 
Rubber  dam,  80 

clamp,  79 

forceps,  79 

punches,  86 
Rules  for  resistance  form,  103 


Saw,  62 

Sawing  and  filing  sections,  31 

Scaler,  62 

Scalpel,  61 

Scissors,  81 

Seat,  105,  no 

Secondary  polish,  88 

Sections,  annotating  or  labeling,  34 

apical,  34 

crown,  34 

curved,  36 

longitudinal,  31 

mid-root,  the,  36 

mounting  the,  S3>  35 

sawing  and  filling  of,  31 

transverse,  31,  3^, 
Semi-cohesive  foils,  149 
Separator,  77 
Se[)tic  condition,  167 


2o6 


INDEX 


Shanks,  angles  in,  45 
Sharpening  instruments,  66,  88 
Silhouettes,  36 

making,  36 

directions  for  making,  36 
Silver,  133 

metallurgical  properties  of,  133 
Simple  dovetail  mortise,  102 

mortise,  102,  103,  104,  108 
Slow-setting  alloys,  135 
Smooth  broaches,  73 

making,  42 
Soap  blocks,  26 

carving  teeth  in,  26 

ivory,  26 

Procter  &  Gamble's,  26 
Soap-stone,  26 
Solila,  150 

Spatula,  70,  125,  129,  139,  141 
Spelling  bee,  184 
Splitting  teeth,  118 
Spoon  excavator,  56,  57 
Spheroiding,  132 
Spring  temper,  88 
Steatite,  26 
Step,  105,  no,  III 

form,  108,  109,  III 
Stepping,  157 

Steps  in  cavity  preparation,  95 
Steel,  41,  42 

technic  work  in,  86 

technical  exercises  in  the   working 
of,  42 

tempering,  42 
Straighten  the  approach,  174 
Strangulation,  169 
Stress,  no 

tipping  or  lifting,  no 
Strips,  63 

Sub-class  names,  56 
Sub-order  names,  56 
Suppuration,  165 
Swiss  broach,  75 
Syringes,  86 

hot-air,  86 

water,  86 
System  of  measurements,    the    French 
decimal,  50 

the  Metric,  49 


Talc,  26 

Technic    for    beveling    and    polishing 
enamel  margins,  115 

for  establishing  the  outline  form,  99 

for  obtaining  resistance,  105 

for  removing  decay,  100 

for  retention  form,  n  i 

of  carving  teeth,  27 

work  in  brass,  88 
in  steel,  86 

forms,  192,  193,  194,  195 
Technical  exercises  (cavity  preparation) , 
116 

(for  mortise  forms),  102 

in  working  steel,  42 
Temper,  spring,  44,  88 
Tempering,  44,  88 
Tempering  steel,  42 
Temporary  filling  materials,  122 

stopping,  124 
Ten  rules  for  plugging  gold,  157 
Tenney's  ivory  blocks,  8,  27 
Ternary  (Amalgams),  134 
Tertiary  polish,  88 
Testing  steel,  88 
The  vernier,  53,  54 
Tin,  133,  138 

advantages  of,  142 

characteristics  of,  138 

cohesive,  138 

disadvantages  of,  143 

metallurgical  properties  of,  133 

method  of  working,  143 

non-cohesive,  158 
Tipping  stress,  no 
Toilet  of  the  cavity,  performing    the, 

116 
Tooth,  definition  of  a  human,  38 
Traction  separator,  77 
Transverse  sections,  31,  33 
Trapezoid,  13,  20 
Trapezoidal,  13,  18,  21 
Treatment  of  devital  pulps,  170 

of  vital  pulps,  168 
Triangle,  molar,  20 
Trimmer,  63 
Triple  an"]e,  46 

contra-angles,  46 
Twist  broach,  73,  76,  176 
Typodont,  119,  192 


Table  of  approximate  temperatures  for 

tempering  steel,  42 
of  comparison  of  Centigrade  with 

astronomical  degrees,  51 
of  measurements  of  the  teeth,  n, 

12 


V 

Vegetable  ivory,  8,  27 
Venous  hypersemia,  164 
Vernier,  the,  53,  54 
Vital  pulp,  166 
Vulnerable  areas,  97 


INDEX 


207 


W 


Wall,  91 

names,  92 
Water  syringes,  86 
Wedge,  13 

separator,  77 

shape,  13 
Wedging,  136,  143,  158 
Welding,  148 
Wenker  odontotypes,  192,  193,  194 


Wheel,  63 

Wood  blocks,  8 

Working  of  steel,  technical  exercises  in, 

42 
Wrapping  cotton  on  smooth  broaches, 
177 


Zinc,  134 

metallurgical  properties  of,  134 


COLUMBIA  UNIVERSITY  LIBRARY 

This  book  is  due  on  the  date  indicated  below,  or  at  the 
expiration  of  a  definite  period  after  the  date  of  borrowing, 
as  provided  by  the  rules  of  the  Library  or  by  special  ar-  , 
rangement  with  the  Librarian  in  charge. 

DAW  SORROWED* 

■^^^ATE  DUE 

DATE  BORROWED 

DATE  DUE 

h}'H  2  0    il 

i43 

ims 

•sr-r  (•■ 

1 

1 

C28(239)MI00 

j 

MoGehe^ 


Ji'R  2  0  1943 


Z'//:- 


